Math in Focus Grade 4 Chapter 9 Answer Key Angles

Practice the problems of Math in Focus Grade 4 Workbook Answer Key Chapter 9 Angles to score better marks in the exam.

Math in Focus Grade 4 Chapter 9 Answer Key Angles

Math Journal

Question 1.
Which statements are wrong? Explain your answer.

a. Two right angles form a \(\frac{1}{2}\)-turn.
Answer:
Yes.

Explanation:
Yes, two right angles form a \(\frac{1}{2}\)-turn.

b. The measure of an angle is a fraction of a \(\frac{3}{4}\)-turn.
Answer:

c. An acute angle has a measure greater than 90°.
Answer:
Wrong.

Explanation:
No, because the acute angle will be less than 90°. So the statement is wrong.

d. A \(\frac{1}{4}\)-turn is 90°.
Answer:
Yes.

Explanation:
Yes, a \(\frac{1}{4}\)-turn is 90°.

e. A straight angle has a measure of 180°.
Answer:
Yes.

Explanation:
Yes, a straight angle has a measure of 180°.

f. 150° is between a \(\frac{1}{4}\) -turn and a \(\frac{1}{2}\)-turn.
Answer:
Yes.

Explanation:
Yes, 150° is between a \(\frac{1}{4}\) -turn and a \(\frac{1}{2}\)-turn.

Complete.

Question 2.
Conrad named the angle as shown. Is he correct? Explain your answer.
Math in Focus Grade 4 Chapter 9 Answer Key Angles 1
The names of the angle are ∠EFG, ∠FGE, and ∠F.
Answer:
Wrong.

Explanation:
The names of the angle ∠FGE, and ∠F are wrong because the middle point must be a vertex.

Put On Your Thinking cap!

Challenging Practice

Look at the clock. The hour hand and minute hand were at the position as shown in figure A. Figure B shows the position of the hour hand and minute hand after some time.
Math in Focus Grade 4 Chapter 9 Answer Key Angles 2
What fraction of a turn did the minute hand move? Explain your answer.

Answer:
The fraction will be \(\frac{1}{4}\).

Explanation:
Here, the fraction of a turn did the minute hand move is \(\frac{1}{4}\).

Put on Your Thinking Cap!

Problem Solving

Look at the diagram.
Tom walks from J to K and at that point makes a \(\frac{1}{4}\)-turn to his right.
Then, he walks to H and at that point, makes a \(\frac{1}{2}\)-turn before walking on to the end of that line.
Where will he be?

Math in Focus Grade 4 Chapter 9 Answer Key Angles 3

Answer:
Tom will be on G.

Explanation:
Here, Tom walks from J to K and at that point makes a \(\frac{1}{4}\)-turn to his right which is 90°, and then he walks to H, and at that point, makes a \(\frac{1}{2}\)-turn which is 180° before walking on to the end of that line. So he will be at point G.

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