Answer : 39
Step-by-step explanation:
Since angles 3 and 4 are supplementary, the add up to 180.
3 + 4 = 180
Substitute the 4 for 81
3 + 81 = 180
Simplify
3 = 99
So, a triangle’s angles add up to 180
1 + 2 + 3 = 180
Substitute 1 and 3 in
42 + 2 + 99 = 180
2 = 39
