Question

what is
a 98°
b 121°
c 133°
d 141°
1 in the figure, m∠1 = 39° and m∠2 = 82°
unit 2 - lesson 7: comprehension check b

Explanation:

Step1: Find the measure of ∠3

Since ∠1 = 39° and ∠2 = 82°, and the sum of angles in a triangle is 180°, we have ∠3=180° - ∠1 - ∠2.
$$\angle3 = 180°-39° - 82°=59°$$

Step2: Find the measure of ∠4

Because ∠3 and ∠4 are supplementary (they form a linear - pair), so ∠4 = 180°-∠3.
$$\angle4=180° - 59°=121°$$

Answer:

B. 121°