Question

The measures of two of the angles in a triangle are green. Find the measure of the thirs angle. Show your calculations to support your answer.

5-8?

Answer 1

Angles in a triangle add up to 180°.
So all we have to do is subtract the 2 angles we know from 180:

For question 5, we subtract 126.5° and 19° from 180°:
180 - 126.5 - 19 = 34.5°

The same principle applies for the rest.

Question 6:
180 - 65.5 -85 = 29.5°

Question 7:
180 -98.3 -37.5 = 44.2°

Question 8:
180 - 31 - 113 = 36°

Answer 2

In a triangle, the three interior angles always add to 180°

5
m∠3 = 180 - 126.5 - 19 = 34.5°

6
m∠3 = 180 - 65.5 - 85 = 29.5°

7
m∠3 = 180 - 98.3 - 37.5 = 44.2°

8
m∠3 = 180 - 31 - 113 = 36°