All the solutions provided in McGraw Hill My Math Grade 4 Answer Key PDF Chapter 14 Lesson 4 Classify Angles will give you a clear idea of the concepts.
McGraw-Hill My Math Grade 4 Answer Key Chapter 14 Lesson 4 Classify Angles
McGraw Hill My Math Grade 4 Chapter 14 Lesson 4 My Homework Answer Key
Practice
Write the measure of each angle in degrees and as a fraction of a full turn.
Question 1.
____________°, ___________ turn
Answer: 360°, 1 turn
The above figure represents an angle of 360°and 1 turn. The center of the circle is treated as an endpoint of two rays, which forms an angle. 1 turn can be considered as 360 degrees. The rotation is in the clockwise direction, so the angle is said to be positive.
Question 2.
____________°, ___________ turn
Answer: 180°, \(\frac{1}{2}\) turn
The above figure represents an angle of 180°and \(\frac{1}{2}\) turn. The center of the circle is treated as an endpoint of two rays, which forms an angle. \(\frac{1}{2}\) turn can be considered as 180 degrees as \(\frac{1}{2}\)th part of 360 degrees is 180 degrees. The rotation is in the clockwise direction, so the angle is said to be positive.
Question 3.
____________°, ___________ turn
Answer: -90°, –\(\frac{1}{4}\) turn
The above figure represents an angle of -90° and –\(\frac{1}{4}\) turn. The center of the circle is treated as an endpoint of two rays, which forms an angle. \(\frac{1}{4}\) turn can be considered as 90 degrees as \(\frac{1}{4}\)th part of 360 degrees is 90 degrees. The rotation is in the anticlockwise direction, so the angle is said to be negative.
Question 4.
____________°, ___________ turn
Answer: 90°, \(\frac{1}{4}\) turn
The above figure represents an angle of 90°and \(\frac{1}{4}\) turn. The center of the circle is treated as an endpoint of two rays, which forms an angle. \(\frac{1}{4}\) turn can be considered as 90 degrees as \(\frac{1}{4}\)th part of 360 degrees is 90 degrees. The rotation is in the clockwise direction, so the angle is said to be positive.
Classify each angle as right, acute, or obtuse.
Question 5.
Answer: Obtuse angle
An obtuse angle is a type of angle that is always larger than 90° but less than 180°. In other terms, its angle ranges from 90° to 180°. In the given figure, the angle shows an obtuse angle, as it measures more than 90 degrees.
Question 6.
Answer: Right angle
A right angle is an angle that is exactly equal to 90 degrees. In the given figure, the angle shows a right angle, as it measures exactly 90 degrees.
Problem Solving
Question 7.
Mathematical PRACTICE Model Math Classify the angle made by the diver.
Answer: Acute angle
An Acute angle is a type of angle that is always less than 90°. This angle is smaller than the right angle (which is equal to 90 degrees). So, in the figure we can observe that the diver makes an acute angle.
Question 8.
The diver wants to be completely straight as she enters the pool. What will be the measure of the angle her body will form then?
Answer: 180°
As the diver wants to be completely straight as she enters the pool, she has to make 180° with her body. 180° is known as straight angle. It is termed as such because it looks like a straight line.
Vocabulary Check
Write a vocabulary term to complete each sentence.
acute angle
degree
obtuse angle
right angle
Question 9.
The unit used to measure an angle is a _______________.
Answer: degree
The unit used to measure an angle is a degree
Question 10.
An ______________ measures more than 90° and less than 180°.
Answer: obtuse angle
An obtuse angle measures more than 90° and less than 180°. In other terms, its angle ranges from 90° to 180°.
Question 11.
Square corner is another name for a ______________.
Answer: right angle
Square corner is another name for a right angle. A right angle is an angle that is exactly equal to 90 degrees.
Question 12.
An angle that measures 20° is an _______________.
Answer: acute angle
An angle that measures 20° is an acute angle. An Acute angle is a type of angle that is always less than 90°. This angle is smaller than the right angle (which is equal to 90 degrees).
Test Practice
Question 13.
Which is the acute angle?
Answer: C
An Acute angle is a type of angle that is always less than 90°. This angle is smaller than the right angle (which is equal to 90 degrees).