Angles

Angles in a triangle

Name: ______________________________Date: ______________Score: ______ / 20

1.
Two angles of a triangle are 30° and 70°. What is the third angle?
°
2.
Two angles of a triangle are 75° and 30°. What is the third angle?
°
3.
Two angles of a triangle are 80° and 40°. What is the third angle?
°
4.
Two angles of a triangle are 40° and 55°. What is the third angle?
°
5.
Two angles of a triangle are 30° and 130°. What is the third angle?
°
6.
Two angles of a triangle are 35° and 45°. What is the third angle?
°
7.
Two angles of a triangle are 48° and 52°. What is the third angle?
°
8.
Two angles of a triangle are 36° and 106°. What is the third angle?
°
9.
Two angles of a triangle are 100° and 40°. What is the third angle?
°
10.
A right-angled triangle has a right angle (90°) and an angle of 30°. What is the third angle?
°
11.
A right-angled triangle has a right angle (90°) and an angle of 45°. What is the third angle?
°
12.
Two angles of a triangle are 65° and 75°. What is the third angle?
°
13.
Two angles of a triangle are 120° and 35°. What is the third angle?
°
14.
The angles inside a triangle always add up to 180°.
True False
15.
An isosceles triangle has two equal angles.
True False
16.
An isosceles triangle has two equal base angles of 50° each. What is the top (apex) angle?
°
17.
An isosceles triangle has a top angle of 126°. The two base angles are equal. What is each base angle?
°
18.
An isosceles triangle has a top angle of 40°. The two base angles are equal. What is each base angle?
°
19.
An isosceles triangle has a top angle of 100°. The two base angles are equal. What is each base angle?
°
20.
An isosceles triangle has two equal base angles of 55° each. What is the top angle?
°

Answer key

Angles — Angles in a triangle

1.80 °
2.75 °
3.60 °
4.85 °
5.20 °
6.100 °
7.80 °
8.38 °
9.40 °
10.60 °
11.45 °
12.40 °
13.25 °
14.True
15.True
16.80 °
17.27 °
18.70 °
19.40 °
20.70 °