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.

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.

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?

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.