Complete the statements to find the measurements of ∠a

and ∠b
.

A triangle with angles labeled a, b, and 50 degrees. A line extends from angle a to form exterior angle with measure 100 degrees.

CLEARCHECK
Find the measurement of ∠a
.
m ∠a +
°=180°

m ∠a=
°
Find the measurement of ∠b
using the measures of the other two angles in the triangle.
m ∠b +

°+

°=180°

m ∠b=

°

3 answers

m ∠a + 100° = 180°
m ∠a = 80°

b = 180° - a - 50°
b = 180° - 80° - 50°
b = 50°
Two angles are complementary.
One of the angles has a measure of 20°
.

What is the measure of the other angle?

A ray extends from an angle to create 2 angles. 1 angle has measure 20 degrees and the second angle has measure question mark.
CLEAR CHECK

70°

20°

160°

110°
The measure of the other angle is 70°.

Explanation:
Complementary angles add up to 90°. Since one angle has a measure of 20°, its complement must have a measure of 90° - 20° = 70°.