Practice the problems of Math in Focus Grade 4 Workbook Answer Key Chapter 9 Practice 1 Understanding and Measuring Angles to score better marks in the exam.

## Math in Focus Grade 4 Chapter 9 Practice 1 Answer Key Understanding and Measuring Angles

**Name the angles in two ways.**

Example

Question 1.

Answer:

∠STU or ∠UTS.

Explanation:

The name of the angle T is ∠STU or ∠UTS.

Question 2.

Answer:

∠XYZ or ∠ZYX.

Explanation:

The name of the angle Y is ∠XYZ or ∠ZYX.

Question 3.

Angle at A: ∠___ or ∠___

Angle at B: ∠___ or ∠___

Angle at C: ∠___ or ∠___

Answer:

∠BAC or ∠CAB,

∠ABC or ∠CBA,

∠BCA or ∠ACB.

Explanation:

The name of angle A is ∠BAC or ∠CAB.

The name of angle B is ∠ABC or ∠CBA.

The name of angle A is ∠BCA or ∠ACB.

**Name the marked angles in two ways.**

Example

∠p: ∠__AED__ or ∠__DEA__

Question 4.

∠q: ∠____ or ∠_____

Answer:

∠q: ∠EDC or ∠CDE

Explanation:

The marked angle ∠q is ∠EDC or ∠CDE.

Question 5.

∠r: ∠____ or ∠_____

Answer:

∠r: ∠BCD or ∠DCB.

Explanation:

The marked angle ∠r is ∠BCD or ∠DCB.

Question 6.

∠s: ∠____ or ∠_____

Answer:

∠s: ∠BAE or ∠EAB.

Explanation:

The marked angle ∠s is ∠BAE or ∠EAB.

**Name the marked angles in two ways.**

Question 7.

∠PRQ: ∠___ or ∠___

Answer:

∠PRQ: ∠b or ∠QRP.

Explanation:

The name of the marked ∠PRQ is ∠b or ∠QRP.

Question 8.

∠QPR: ∠___ or ∠___

Answer:

∠QPR: ∠a or ∠RPQ.

Explanation:

The name of the marked ∠QPR is ∠a or ∠RPQ.

**Decide which scale you would use to measure each angle.**

**Fill in the blanks with inner scale or outer scale.**

Examples

Question 9.

Answer:

Outer scale.

Explanation:

Here, the angle opens to the left of the protractor, so the shown image is an outer scale.

Question 10.

Answer:

Outer scale.

Explanation:

Here, the angle opens to the left of the protractor, so the shown image is an outer scale.

Question 11.

Answer:

Inner scale.

Explanation:

Here, the angle opens to the right of the protractor, so the shown image is an inner scale.

Question 12.

Answer:

Inner scale.

Explanation:

Here, the angle opens to the left of the protractor, so the shown image is an inner scale.

**Peter is walking along a path. Measure the marked angles along this path.**

Question 17.

Answer:

Explanation:

Here, the measure of ∠FGH = 80°,

the measure of ∠EFG = 75°,

the measure of ∠CDE = 80°,

the measure of ∠GHI = 20°,

the measure of ∠DEF = 70°