Answer:
110
Explanation:
To find the measure of the exterior angle we first need to find the value of t.
The sum of interior angles in a triangle is equal to 180° so we can write the following equation:
t + 10 + t + t + 20 = 180 add like terms
3t + 30 = 180 subtract 30 from both sides
3t = 150 divide both sides by 3
t = 50
The exterior angles and the angle represented with t + 20 make a straight line
and they are supplementary angles so their sum is equal to 180
t + 20 = 70 to complete this to 180 we need 110