All the solutions provided in **McGraw Hill My Math Grade 3 Answer Key PDF Chapter 14 Lesson 3 Triangles **will give you a clear idea of the concepts.

## McGraw-Hill My Math Grade 3 Answer Key Chapter 14 Lesson 3 Triangles

**Measure It**

Measure the sides of each pair of triangles below to the nearest quarter of an inch. Then record the measurements.

Triangle A

Triangle B

Triangle C

Triangle D

Answer:

Measure the above triangles side length using the measuring scale.

Triangle A is

The measurements of triangle B is

The measurements of triangle C is

The measurements of triangle D is

**Talk About It**

**Identify each triangle with what you discovered about the side lengths.**

Question 1.

No side lengths are the same.

Triangle(s) _____________

Answer:

In triangle D no side lengths are the same.

Question 2.

All 3 side lengths are the same.

Triangle(s) _____________

Answer:

In triangle A and triangle B all 3 side lengths are the same.

Question 3.

Exactly 2 side lengths are the same.

Triangle(s) _____________

Answer:

In triangle C exactly 2 side lengths are the same.

A triangle with one right angle is called a right triangle. Find the right triangle in the photo to the right.

**Try It**

Compare the angles of each triangle below. Which triangle is a right triangle? Circle it.

Which triangle did you circle? Explain why you chose that triangle.

So, Triangle ____________ is a right triangle.

Answer:

The triangle A is the right triangle. because the angle is formed at the corner of the square.

**Talk About It**

**Mathematical PRACTICE** Draw a Conclusion Refer to the activity above for Exercises 4-5.

Question 4.

Which triangle has an angle greater than a right angle?

Answer:

The triangle B has an angle greater than a right angle.

Question 5.

Which triangle has all 3 angles that are less than a right angle?

Answer:

The triangle C has all 3 angles that are less than a right angle.

Question 6.

Explain how a triangle is a special kind of polygon.

Answer:

The triangle is special kind of polygon. It has only 3 sides. for the polygon one or two sides are possible. Triangle is least number of possible sides. So, it is polygon.

**Practice It**

**Measure the sides of each triangle below to the nearest quarter of an inch. Then state the number of sides with equal lengths.**

Question 7.

____________ sides

Answer:

Using the measuring scale find the length of each side.

The length of each side of the triangle is

The triangle has 3 equal sides.

Question 8.

____________ sides

Answer:

Using the measuring scale find the length of each side.

The length of each side of the triangle is

The triangle has 2 equal sides.

Question 9.

____________ sides

Answer:

Using the measuring scale find the length of each side.

The length of each side of the triangle is

The triangle has no equal sides.

Question 10.

____________ sides

Answer:

Using the measuring scale find the length of each side.

The length of each side of the triangle is

The triangle has no equal sides.

**Compare the angles of each triangle. Then circle the correct description.**

Question 11.

1 right angle

1 angle is greater than a right angle.

Answer:

In the given triangle one angle is greater than a right angle.

Question 12.

1 right triangle

3 angles are less than a right angle.

Answer:

Given triangle is 1 right triangle

Question 13.

3 angles are less than a right angle.

1 angle is greater than a right angle.

Answer:

In the given triangle the 3 angles are less than a right angle.

Question 14.

1 right angle

1 angle is greater than a right angle.

Answer:

In the given triangle the 1 right angle is greater than a right angle.

Question 15.

Circle the triangles on this page that are right triangles.

Answer:

There are 2 right triangles on this page they are

**Apply It**

Question 16.

One side of the Egyptian pyramid is in the shape of a triangle. Circle the phrase that best describes the angles of the triangle.

all angles are greater than a right angle

all angles are less than a right angle

one angle is a right angle

Answer:

Given that,

One side of the Egyptian pyramid is in the shape of a triangle.

In the triangle all angles are less than a right angle.

Question 17.

**Mathematical PRACTICE** Be Precise Measure the sides of the triangle to the nearest quarter of an inch. Then state the number of sides with equal lengths.

______________ sides of equal length

Answer:

The measurements of the triangle to the nearest quarter of an inch.

There are 2 equal lengths.

Question 18.

**Mathematical PRACTICE** Identify Structure Draw a triangle that is a right triangle. Then draw a triangle that is not a right triangle.

Answer:

Given that,

Draw a triangle that is a right triangle. Then draw a triangle that is not a right triangle.

Here the right triangle and not a right triangle is drawn.

**Write About It**

Question 19.

How are all triangles the same and how can they be different?

Answer:

All triangles are similar when the corresponding angles are congruent. The similar triangles have same shape but they have different size.

### McGraw Hill My Math Grade 3 Chapter 14 Lesson 3 My Homework Answer Key

**Practice**

**Measure the sides of each triangle below to the nearest quarter of an inch. Then state the number of sides with equal lengths.**

Question 1.

____________ sides

Answer:

The measurements of the triangle are

There are 3 equal sides.

Question 2.

____________ sides

Answer:

The measurements of the triangle are

There are no equal sides.

**Compare the angles of each triangle. Then circle the correct description.**

Question 3.

3 angles are less than a right angle

1 right angle.

Answer:

In the given triangle 3 angles are less than a right angle.

Question 4.

3 angles greater than a right angle

1 angle is greater than a right angle

Answer:

The given triangle has 1 angle is greater than a right angle.

**Problem Solving**

Question 5.

Mathe**matical PRACTICE **Be Precise In billiards, a rack is used to organize billiard balls at the beginning of the game. Measure the sides of the triangle shown. What is the length of each side to the nearest quarter inch?

Answer:

Given that,

The length of the triangle is

The triangle has 3 equal sides.

Question 6.

Refer to Exercise 5. How many angles are less than a right angle?

Answer:

The all the 3 angles are less than than a right angle.

Question 7.

How many angles are less than a right angle in the triangle shown at the right?

Answer:

All the three angles less than a right angle in the triangle.

**Vocabulary Check**

**Fill in the missing word.**

Question 8.

A triangle with one right angle is called a ______________ triangle.

Answer:

A triangle with one right angle is called a right triangle.