Into Math Grade 8 Module 13 Lesson 1 Answer Key Find Volume of Cylinders

We included HMH Into Math Grade 8 Answer Key PDF Module 13 Lesson 1 Find Volume of Cylinders to make students experts in learning maths.

HMH Into Math Grade 8 Module 13 Lesson 1 Answer Key Find Volume of Cylinders

I Can find the volume of a cylinder or the dimensions of a cylinder given the volume.

Spark Your Learning

You have seen that the volume of a rectangular prism is the area of the base times the height. This may be written as V = Bh. Since the area of the rectangular base is the length times the width, the formula can also be written as V = lwh.

The base of a cylinder is a circle. What is the volume of the cylinder shown? (Hint Recall that the formula for the area A of a circle is A = πr²) Show your steps.
Answer:
The volume of a cylinder = πr²h cubic units.
Given, r = 2
h = 3
we know that, π = 3.14 (or) 22/7
Now substitute the values in the formula.
The volume of cylinder = 3.14 x 2^2 x 3
The volume of cylinder = 3.14 x 4 x 3
The volume of cylinder = 37.68 cubic inches.

Turn and Talk How is finding the volume of a cylinder similar to finding the volume of a rectangular prism? How is it different?
Answer:
They are both similar in the way that the formula is base multiplied by height. They are different becasue of the type of shape on the base. The formula for any prism would be base x height.

Build Understanding

The formula for the volume of a cylinder is similar to the formula for the volume of a rectangular prism. The formula states that the volume V is the product of the area of the base B and the height h. The only difference is in how to calculate B. You can use the fact that the base of a cylinder is a circle to write the formula in terms of the radius r.

V = Bh
or
V= πr²h

Connect to Vocabulary
A cylinder is a three-dimensional figure with two parallel congruent circular bases connected by a curved lateral surface.

Question 1.
Find the volume of the cylindrical can of tomato soup shown. Leave your answer in terms of π.

A. What information do you need to know in order to use the formula V= πr²h?
Answer:
We should know the ‘r-value and h value
we already know the π which is 3.14 or 22/7.

B. What are the radius and the height of the cylinder?
Answer:
The radius of the cylinder given its 3.5cms
The height of the cylinder given its 10.5cms

C. Show how to substitute for r and h in the formula. Then simplify and leave your answer in terms of ir. Be sure to include an appropriate unit for the volume.
Answer:
The volume of cylinder formula is:
V = πr²h
V = π x 3.5^2 x 10.5
In the above question, the answer should be π. So we are not substituting the value of π.
V = π x 12.25 x 10.5
V = 128.625π.

D. Now show how to use 3.14 as an approximation for π. Round the volume to the nearest tenth.
Answer:
Here, we have to substitute the π value.
In the above part C question, we got the answer V = 128.625π
V = 128.625 x 3.14
V = 403.8825
The neraest tenth value is 404 cubic centimetres.

Turn and Talk How can you use estimation to show that the volume you found is reasonable?
Answer:
We got the volume V = 403.8825
we need to write the estimation value to the nearest tenth.
– First of all, we need to check the value of the unit.
– The unit’s value is less than 5 the values remain the same.
– The unit’s value is greater than 5 or equal to 5 then all the digits become zero.

Step It Out

Question 2.
You can find the volume of a cylinder when you know the radius (or diameter) of the cylinder and its height.

A. Find the volume of the cylindrical vase shown. Use \(\frac{22}{7}\) for π.
The radius is inches.
The height is __________ inches.
Substitute values for the radius r and the height h. Substitute \(\frac{22}{7}\) for π..
V = πr²h

The volume of the cylinder is approximately ___________ cubic inches.
Answer:
The volume of the cylinder V = πr²h
radius = 7/2
height = 20
substitute the values in the formula.
V = 22/7 x 7/2 x 20
V = 3.14 x 3.5 x 20
V = 219.8 cubic inches.
Therefore, the volume of the cylinder is approximately 220 cubic inches.

B. Find the volume of the cylinder shown. Leave the answer in terms of π and then use 3.14 for π. Express the volume in scientific notation and round the first factor to the nearest tenth.

The diameter is 2.4 × 10^-2 centimeter, so the radius is __________ × centimeter.
Now use the formula for the volume of a cylinder. Substitute values for the radius r and the height h.
V = πr²h
= π(___________ × 10^-2)² (_________ × 10^-2)
= π(___________ × 10^-4) (_________ × 10^-2)
= π(__________ × )
≈ (3.14) (_________ × )
≈ ___________ × 10^-6
≈ ___________ × 10^-5
The volume of the cylinder is (___________ × 10^-6)π, or approximately ____________ × 10^-5 cubic centimeter.
Answer:
Above-given information:
diameter = 2.4 x 10^-2 = 0.024
from this, we need to find the radius.
radius of circle= diameter/2
radius = 0.024/2
radius = 0.012
radius = 1.2 x 10^-2
height = 4.1 x 10^-2
Now we know the values of radius and height. Now substitute the values in the formula.
The volume of cylinder V = πr²h
V = 3.14 x (1.2 x 10^-2)^2 x (4.1 x 10^-2)
V = 3.14 x (1.2 x 10^-2)(1.2 x 10^-2) x (4.1 x 10^-2)
apply this formula: [a^m x a^n = a^m+n]
10^-2 . 10^-2 = 10^-2+(-2) = 10^-2-2 = 10^-4
V = 3.14 x (1.44 x 10^-4) x (4.1 x 10^-2)
V = 3.14 x (5.904 x 10^-6)
After calculating the above equation we get:
V = 0.000018
This can be written as:
V = 1.8 x 10^-5
Therefore, the volume of the cylinder is (5.904 x 10^-6)π, and approximately 1.8 x 10^-5 cubic centimetres.

Question 3.
The volume of the cylinder shown is 602.88 ft³. Find the height of the cylinder. Use 3.14 for π. (Note that the height of a cylinder is not always a vertical distance.)

A. Use the formula for the volume of a cylinder. Substitute the known values for the volume V and for the radius r. Use 3.14 for π. Then solve for h.
V = πr²h
___________ ≈ (3.14) (____________)² h
___________ ≈ (3.14) (____________) h
____ ≈ ____________
The height of the cylinder is approximately ___________ feet.
Answer:
Above-given information:
The volume of the cylinder = 602.88 cubic feet
radius = 4 feet
we need to find out the height of the cylinder.
Height = h
We know the formula,
V = πr²h
Now substitute the values.
602.88 = 22/7 x 4 x 4 x h
602.88 = 3.14 x 16 x h
602.88 = 50.24 x h
Now take ‘h’ into left hand side.

Therefore, the height of the cylinder is 12 feet.

B. How can you check that your answer is reasonable?
The height is ____________ feet, the radius is ____________ feet, and π rounded to the nearest whole number is ___________.
The volume is approximately = cubic feet.
This is close to the given volume, so the answer is reasonable.
Answer:
From the above information in part A,
the height is 12 feet
radius is 4 feet
π = 3.14
Now substitute in the formula.
The volume of a cylinder V = πr²h
V = 3.14 x 4 x 4 x 12
V = 3.14 x 16 x 12
V = 602.88 cubic feet.
Therefore, the answer is reasonable.

Check Understanding

Question 1.
What information do you need to know in order to find the volume of a cylinder?
Answer:
To calculate its volume, we need to know two parameters:
– radius and height.
And we know the formula:
The volume of a cylinder V = πr²h
Finally, we substitute the radius value and height value.
And we know the π value which is 22/7 or 3.14

Question 2.
The volume of this cylinder is 32π yd³. Find the height.

Answer:
Above-given information:
The volume of the cylinder = 32π cubic yards
radius = 4 yards
we need to find out the height of the cylinder.
Height = h
We know the formula,
V = πr²h
Now substitute the values.
32π = 22/7 x 4 x 4 x h
32π = 3.14 x 16 x h
32π = 50.24 x h
Now take ‘h’ on the left-hand side.
32π/h = 50.24
h x 50.24 = 32π
h = 32π/50.24
h = 0.63π
h = 0.63 x 3.14
h = 1.9782 yards
Therefore, the height of the cylinder is 1.9782 yards.

Question 3.
Find the volume. Use 3.14 for π. Round the volume to the nearest tenth.

Answer:
Above-given information:
the height is 7.2 m
diameter = 2.8
radius = d/2 = 2.8/2 = 1.4 m
radius is 1.4m
π = 3.14
Now substitute in the formula.
The volume of a cylinder V = πr²h
V = 3.14 x 1.4 x 1.4 x 7.2
V = 44.31
Therefore, the volume of the cylinder is 44.31 cubic metres.

On Your Own

Question 4.
Attend to Precision The height of the cylindrical container shown is 7 inches.

A. Find the volume of the cylinder. Leave your answer in terms of π.
Answer:
Above-given information:
radius = 2 inches
height = 7 inches
We know the formula:
The volume of a cylinder V = πr²h
V = π x 2 x 2 x 7
V = π x 4 x 7
V = 28π
Therefore, the volume of a cylinder in terms of π is 28π.

B. Find the volume of the cylinder. This time, use \(\frac{22}{7}\) for π. ________
Answer:
Above-given information:
radius = 2 inches
height = 7 inches
π = 22/7 = 3.14
We know the formula:
The volume of a cylinder V = πr²h
V = 3.14 x 2 x 2 x 7
V = 3.14 x 28
V = 87.92 cubic inches.
Therefore, the volume of a cylinder after substituting the π value is 87.92 cubic inches.

C. Find the volume of the cylinder. Use 3.14 for π. Round the volume to the nearest tenth.
Answer:
In the above information (part B), we got the volume of a cylinder is 87.92 cubic inches.
The nearest tenth value is 87.90

D. Which of the volumes that you calculated, if any, are the exact volume? Which are approximations? Explain.
Answer:
From the above-given information in part A and part B, we calculated volumes.
V = 32 π (part A)
V = 87.92 (part B)
Both are exact volumes.
V = 87.92 (part B) are approximate value because we estimated this value to the nearest tenth. So the approximate value is 87.90 cubic units.

For Problems 5-6, find the volume of each cylinder. Use 3.14 for π. Round the volume to the nearest tenth.

Question 5.

Answer:
Above-given information:
radius = 1.8 inches
height = 5.1 inches
π = 22/7 = 3.14
We know the formula:
The volume of a cylinder V = πr²h
Now substitute the values in the formula.
V = 3.14 x 1.8 x 1.8 x 5.1
V = 51.88 cubic metres.
The nearest tenth is 52
Therefore, the volume of a cylinder is 52 cubic metres.

Question 6.

Answer:
Above-given information:
the height is 1.7 cm
diameter = 4.2
radius = d/2 = 4.2/2 = 2.1cms
radius is 2.1cm
π = 3.14
Now substitute in the formula.
The volume of a cylinder V = πr²h
V = 3.14 x 2.1 x 2.1 x 1.7
V = 3.14 x 7.497
V = 23.54058
The nearest tenth value is 24.
Therefore, the volume of a cylinder is 24 cubic cms.

For Problems 7-8, the table shows the radius and height for three different cylinders.

Question 7.
Construct Arguments Without calculating, which cylinder has the greatest volume? Explain.
Answer:
Above-given information for A cylinder:
radius = 2 ft
height = 4 ft
π = 22/7 = 3.14
We know the formula:
The volume of a cylinder V = πr²h
V = 3.14 x 2 x 2 x 4
V = 3.14 x 16
V = 50.24 cubic feet
Above-given information for B cylinder:
radius = 4 ft
height = 6 ft
The volume of a cylinder V = πr²h
V = 3.14 x 4 x 4 x 6
V = 3.14 x 96
V = 301.44 cubic ft
Above-given information for C cylinder:
radius = 4 ft
height = 4 ft
V = 3.14 x 4 x 4 x 4
V = 3.14 x 64
V = 200.96 cubic ft.
By comparing all these volumes, the greatest one is the B cylinder.

Question 8.
What is the ratio of the volume of Cylinder C to the volume of Cylinder A?
Answer:
ratio = volume of cylinder C/volume of cylinder A
ratio = 200.96/50.24
ratio = 4/1
Therefore, the ratio is 4:1

For Problems 9-12, find the approximate height of each cylinder. Use 3.14 for π.

Question 9.
Volume = 37.68 in³

Answer:
Above-given information:
The volume of the cylinder = 37.68 cubic inches
radius = 2 inches
we need to find out the height of the cylinder.
Height = h
We know the formula,
V = πr²h
Now substitute the values.
37.68 = 22/7 x 2 x 2 x h
37.68 = 3.14 x 4 x h
37.68 = 12.56 x h
Now take ‘h’ on the left-hand side.
37.68/h = 12.56
h x 12.56 = 37.68
h = 37.68/12.56
h = 3
Therefore, the height of the cylinder is 3 inches

Question 10.
Volume = 146.952 cm³

Answer:
Above-given information:
The volume of the cylinder = 146.952 cubic cms
diameter = 6cm
radius = d/2 =6/2 = 3
radius = 3 cms
we need to find out the height of the cylinder.
Height = h
We know the formula,
V = πr²h
Now substitute the values.
146.952 = 22/7 x 3 x 3 x h
146.952 = 3.14 x 9 x h
146.952 = 28.26 x h
Now take ‘h’ on the left-hand side.
146.952/h = 28.26
h x 28.26 = 146.952
h = 146.952/28.26
h = 5.2 cms
Therefore, the height of the cylinder is 5.2 inches

Question 11.
Volume = 196.25 mm³

Answer:
Above-given information:
The volume of the cylinder = 196.25 cubic mm
radius = 2.5 mm
we need to find out the height of the cylinder.
Height = h
We know the formula,
V = πr²h
Now substitute the values.
196.25 = 22/7 x 2.5 x 2.5 x h
196.25 = 3.14 x 6.25 x h
196.25 = 19.625 x h
Now take ‘h’ on the left-hand side.
196.25/h = 19.625
h x 19.625 = 196.25
h = 196.25/19.625
h = 10
Therefore, the height of the cylinder is 10 mm

Question 12.
Volume = 48.2304 m³

Answer:
Above-given information:
The volume of the cylinder = 48.2304 cubic metre
diameter = 6.4 m
r = d/2 = 6.4/2 = 3.2
radius = 3.2 m
we need to find out the height of the cylinder.
Height = h
We know the formula,
V = πr²h
Now substitute the values.
48.2304 = 22/7 x 3.2 x 3.2 x h
48.2304 = 3.14 x 10.24 x h
48.2304 = 32.15 x h
Now take ‘h’ on the left-hand side.
48.2304/h = 32.15
h x 32.15 = 48.2304
h = 48.2304/32.15
h = 1.50 m
Therefore, the height of the cylinder is 1.50m

Question 13.
Find the approximate volume of the cylinder shown. Use 3.14 for π. Express the volume in scientific notation and round the first factor to the nearest tenth.

Answer:
Above-given information:
height = 1.2 x 10^4
radius = 6 x 10^3
We know the formula,
V = πr²h
V = 3.14 x (6 x 10^3)(6 x 10^3) x (1.2 x 10^4)
V = 3.14 x (36 x 10^6) x (1.2 x 10^4)
V = 3.14 x (43.2 x 10^10)
V = 135.648 x 10^10
Therefore, the volume of the cylinder is 135.648 x 10^10 cubic mm.

Question 14.
Open-Ended Give the radius and height of a cylinder whose volume is greater than 1000 cubic feet but less than 2000 cubic feet.
Answer:

Question 15.
Attend to Precision Consider a cylinder with the radius and height shown in the image.

A. Find the approximate volume of the cylinder using the π key on your calculator. Round your answer in a way that seems most appropriate.
Answer:
Above-given information:
radius = 3.55 cms
height = 3.55 cms
π = 22/7 = 3.14
We know the formula:
The volume of a cylinder V = πr²h
V = 3.14 x 3.55 x 3.55 x 3.55
V = 3.14 x 44.73
V = 140.45
Therefore, the volume of the cylinder is 140.45 cubic cms

B. Explain how you decided how many digits to include in your answer.
Answer:

I’m in a Learning Mindset!

What is challenging about using the formula for the volume of a cylinder? Where can I go to get help if needed?
Answer:
– Finding the radius of the circular base
– Calculate the area of the circular base
– Find the height of the cylinder
– Multiply the area of the base by the height.
– Always state your final answer in cubic units because the volume is the measure of a three-dimensional space.

Lesson 13.1 More Practice/Homework

Question 1.
The radius of a cylinder is 49 feet, and the height is 180 feet. Find the volume of the cylinder. Leave your answer in terms of π.

Answer:
Above-given information:
radius = 49 feet
height = 180 feet
π = 3.14
We need to find out the volume of the cylinder V.
Now substitute in the formula.
The volume of a cylinder V = πr²h
V = 3.14 x 49 x 49 x 180
V = 3.14 x 2401 x 180
V = 1357045.2
Therefore, the volume of the cylinder is 1357045.2 cubic feet.

Question 2.
Math on the Spot Find the approximate volume of each cylinder. Use 3.14 for π. Round the volume to the nearest cubic unit if necessary.
A.

Answer:
Above-given information:
radius = 5 in
height = 12 in
π = 3.14
We need to find out the volume of the cylinder V.
Now substitute in the formula.
The volume of a cylinder V = πr²h
V = 3.14 x 5 x 5 x 12
V = 3.14 x 25 x 12
V = 942.
The nearest unit was cubic inches
Therefore, the volume of a cylinder is 942 cubic inches.

B.

Answer:
Above-given information:
diameter = 8 ft
r = d/2 = 8/2 = 4
radius = 4 ft
height = 20 ft
π = 3.14
We need to find out the volume of the cylinder V.
Now substitute in the formula.
The volume of a cylinder V = πr²h
V = 3.14 x 4 x 4 x 20
V = 3.14 x 16 x 20
v = 3.14 x 320
v = 1004.8
Therefore, the volume of a cylinder is 1004.8 cubic ft.

C.

Answer:
Above-given information:
radius = (h/3 + 1) cms
We can substitute h value in radius.
r = 18/3 + 1
r = 6 + 1
r = 7 cms
h = 18 cms
π = 3.14
We need to find out the volume of the cylinder V.
Now substitute in the formula.
The volume of a cylinder V = πr²h
V = 3.14 x 7 x 7 x 18
V = 3.14 x 49 x 18
V = 2769.48
therefore, the volume of the cylinder is 2769.48 cubic cms.

For Problems 3-4, approximate the volume of each cylinder. Use 3.14 for π. Round the volume to the nearest cubic unit if necessary.

Question 3.

Answer:
Above-given information:
diameter = 8.2 ft
r = d/2 = 8.2/2 = 4.1
radius = 4.1 ft
height = 9.1 ft
π = 3.14
We need to find out the volume of the cylinder V.
Now substitute in the formula.
The volume of a cylinder V = πr²h
V = 3.14 x 4.1 x 4.1 x 9.1
V = 3.14 x 16.81 x 9.1
v = 3.14 x 152.971
v = 480.32
Therefore, the volume of a cylinder is 480.32 cubic ft.

Question 4.

Answer:
Above-given information:
radius = 2 cm
height = 5 cm
π = 3.14
We need to find out the volume of the cylinder V.
Now substitute in the formula.
The volume of a cylinder V = πr²h
V = 3.14 x 2 x 2 x 5
V = 3.14 x 4 x 5
V = 62.8
Therefore, the volume of a cylinder is 62.8 cubic cms.

Question 5.
A cylinder has diameter d and height h. Write a formula for the volume V of the cylinder in terms of d and h.
Answer:
above-given information:
diameter = d
height = h
Volume = v
The volume of a cylinder with base radius ‘r’ and height ‘h’, V = πr 2 h. If its base diameter is d, then we have d = r/2. Substituting this in the above formula, we get V = πd 2 h/4. Thus, the formula to find the volume of a cylinder with the diameter (d) and height (h) is
V= πd 2 h/4.

For Problems 6-7, find the approximate height of each cylinder. Use 3.14 for π.

Question 6.
Volume = 7.85 ft³

Answer:
Above-given information:
The volume of a cylinder = 7.85 cubic ft
radius = 1 ft
we need to find out the height of the cylinder.
Height = h
We know the formula,
V = πr²h
Now substitute the values.
7.85 = 3.14 x 1 x 1 x h
7.85 = 3.14 x h
Take ‘h’ on the left-hand side.
7.85/h = 3.14
h x 3.14 = 7.85
h = 7.85/3.14
h = 2.5 ft
Therefore, the height of a cylinder is 2.5 ft

Question 7.
Volume = 668.6944 m³

Answer:
Above-given information:
The volume of a cylinder = 668.6944 cubic metre
radius = 4.4
we need to find out the height of the cylinder.
Height = h
We know the formula,
V = πr²h
Now substitute the values.
668.6944 = 3.14 x 4.4 x 4.4 x h
668.6944 = 3.14 x 19.36 x h
668.6944 = 60.79 x h
Take ‘h’ on the left-hand side.
668.6944/h = 60.79
h x 60.79 = 668.6944
h = 668.6944/60.79
h = 11.00
Therefore, the height of a cylinder is 11.00 m

Test Prep

Question 8.
Which of the following values for the radius and height of a cylinder result in a cylinder with the greatest volume?
(A) radius = 1 ft; height = 4 ft
(B) radius = 2 ft; height = 3 ft
(C) radius = 3 ft; height = 2 ft
(D) radius = 4 ft; height = 1 ft
Answer: Option C is the right answer.
We know the formula,
V = πr²h
For the option A:
V = 3.14 x 1 x 4
V = 12.56 cubic ft
For the option B:
V = 3.14 x 4 x 3
V = 37.68 cubic ft
For the option C:
V = 3.14 x 9 x 2
V = 56.52 cubic ft
For the option D:
V = 3.14 x 16 x 1
V = 50.24 cubic ft
By comparing all the volumes, option C volume is the greatest.

Question 9.
Which value or values for the radius of the cylinder shown results in a cylinder with a volume that is greater than 100 cubic centimeters but less than 600 cubic centimeters? Select all that apply.

(A) 1 cm
(B) 3 cm
(C) 5 cm
(D) 6 cm
(E) 8 cm
(F) 10 cm
Answer: Options B, C and D are correct.
Here we need to do option verification.
V = 3.14 x 1 x 5 = 15.7 cubic cms
V = 3.14 x 9 x 5 = 141.3 cubic cms
V = 3.14 x 25 x 5 = 392.5 cubic cms
V = 3.14 x 36 x 5 = 565.2 cubic cms
V = 3.14 x 64 x 5 = 1004.8 cubic cms
V = 3.14 x 100 x 5 = 1570 cubic cms.
According to the question, the answers will be options B, C, and D.

Question 10.
The cylinder shown has a volume of 62.8 cubic inches. Which of the following is closest to the height of the cylinder?

(A) 5 in.
(B) 10 in.
(C) 20 in.
(D) 30 in.
Answer: Option A is correct.
Above-given information:
The volume of the cylinder = 62.8 cubic inches
radius = 2 in
We need to find out the height ‘h’.
We know the formula,
V = πr²h
62.8 = 3.14 x 4 x h
62.8 = 12.56 x h
62.8/h = 12.56
h x 12.56 = 62.8
h = 62.8/12.56
h = 5
Therefore, the height of the cylinder is 5 in.
Question 11.
The radius of Cylinder P is 6 millimeters, and the radius of Cylinder Q is 3 millimeters. The cylinders have the same height. Which is a true statement about the cylinders?
(A) The volume of Cylinder P is 2 times the volume of Cylinder Q.
(B) The volume of Cylinder P is 4 times the volume of Cylinder Q.
(C) The volume of Cylinder P is 18 times the volume of Cylinder Q.
(D) The volume of Cylinder P is 36 times the volume of Cylinder Q.
Answer:

Spiral Review

Question 12.
Find the height of the cone. Round your answer to the nearest tenth of a centimeter.

Answer:
The volume of a cone, V = (⅓)πr²h cubic units.
radius = 5 cms
slant height = 12 cms
Using cone height formula,
h = √l² – r²
= √(12)² – (5)²
= √144-25
= √119
= 10.90
Therefore, the height of the cone is 10.90 cms.

Question 13.
Write the number 0.0000000058 in scientific notation.
Answer:
All the numbers in scientific notation are written in the form a × 10^b, where b is an integer and the coefficient a is a non-zero real number between 1 and 10 in absolute value.
To convert 0.0000000058 into scientific notation also known as standard form, follow these steps:
1. Move the decimal 9 times to the right in the number so that the resulting number, m = 5.8, is greater than or equal to 1 but less than 10
2. Since we moved the decimal to the right the exponent n is negative
n = -9
3. Write in the scientific notation form, m × 10ⁿ
= 5.8 × 10^-9
Therefore, 0.0000000058 in scientific notation is 5.8 × 10^-9

Question 14.
Find the difference and express your answer in scientific notation.
(3.4 × 10⁶) – (4.9 × 10⁵)
Answer:
= 3400000 – 490000
= 2910000
The scientific notation will be:
2.91 x 10^6.
Therefore, the answer for the (3.4 × 10⁶) – (4.9 × 10⁵) = 2.91 x 10^6.