# Naming Angles Worksheet - Page 2

Naming Angles Worksheet
• Page 2
11.
Match the items in the table.

 a. 1-(ii), 2-(iii), 3-(iv) and 4-(i) b. 1-(iv), 2-(i), 3-(ii) and 4-(iii) c. 1-(iv), 2-(iii), 3-(i) and 4-(ii) d. 1-(ii), 2-(i), 3-(iv) and 4-(iii)

#### Solution:

Figure- (i) represents right angle.

Figure- (ii) represents an acute angle.

Figure- (iii) represents straight angle.

Figure- (iv) represents an obtuse angle.

The correct choice is 1-(iv), 2-(i), 3-(ii) and 4-(iii).

12.
Which of the figures represents the angle 180°?

 a. Figure (d) b. Figure (b) c. Figure (c) d. Figure (a)

#### Solution:

Angle in the Figure (a) represents straight angle. It measures 180°.

Angle in the Figure (b) represents an acute angle. It measures approximately 45°.

Angle in the Figure (c) represents an obtuse angle. It measures approximately 120°.

Figure (d) represents an acute angle of approximately 60°

So, only Figure (a) represents the angle 180°.

13.
Find the measure of the angle in the figure.

 a. 50° b. 100° c. 90° d. 180°

#### Solution:

The angle in the figure represents right angle.

Right angle measures 90°.

So, the measure of the angle in the figure is 90°.

14.
What is the measure of the angle in the figure?

 a. 100° b. 180° c. 90° d. 130°

#### Solution:

The angle in the figure is an obtuse angle.

From the choices, 100°, 130° are the obtuse angles.

In the figure, the angle is not nearer to right angle. So, the measure of the angle in the figure is not 100°.

The measure of the angle in the figure is 130°.

15.
Which of the figures represents an acute angle?

 a. Figure (b) b. Figure (c) c. Figure (a) d. Figure (d)

#### Solution:

Angle in the Figure (a) represents an obtuse angle.

Angle in the Figure (b) represents right angle.

Angle in the Figure (c) represents an obtuse angle.

Angle in the Figure (d) represents an acute angle.

So, Figure (d) is the correct choice.

16.
What kind of angle is $\angle$ABC?

 a. right angle b. obtuse angle c. acute angle d. straight angle

#### Solution:

From the figure, measure of the ABC is less than 90o.

The angle, which is less than 90o is called an acute angle.

So, ABC is an acute angle.

17.
"The sum of two acute angles is equal to an obtuse angle." - Which of the following is correct about this statement?
 a. Always false b. Always true c. Sometimes true d. None of the above

#### Solution:

Obtuse angle measures greater than 90o and less than 180o.
Acute angle measures less than 90o

Consider the two acute angles as 35oand 50o. The sum of the two angles is 85o.

85o is an acute angle. So, the statement is false.

Consider the two acute angles as 67o and 76o. The sum of the angles is 143o.

143o is an obtuse angle. So, the statement is true.

So, the statement is sometimes true and sometimes false.

18.
Choose the term that properly comments on the validity of the statement, 'Straight angle is another name for an obtuse angle'.
 a. Always true b. Sometimes false c. Always false d. None of the above

#### Solution:

A straight angle should measure exactly 180o whereas an obtuse angle measures more than 90o and less than 180o.

So, an obtuse angle never measures 180o.

So, the statement is always false.

19.
Select the term that correctly comments on the validity of the statement, 'Two times the measure of an obtuse angle is equal to the measure of the straight angle'.
 a. Sometimes it can be false b. Always false c. Always true d. None of the above

#### Solution:

The measure of an obtuse angle is more than 90o and less than 180o.

Straight angle measures 180o.

Two times the measure of an obtuse angle is greater than 180o.

So, the statement is always false.

20.
Which of the following sides form the angle 60o in the figure?

 a. BD and BC b. CB and DB c. AB and BD d. AB and BC

#### Solution:

Angle is made up of two sides with a common end point.

From the figure the angle 60o is made up of two sides AB and BC.