Using compatible numbers to estimate 83+34

 80 + 30
then add
80 + 30=110
then add the numbers you left out
3+ 4 = 7
and you get 117

or you can round up
90 + 40
90 + 40=130
then you subtract the numbers you added on
90 - 83 = 7
40 - 34 = 6
then you add those and subtract from 130 and you get 11Answer here

This polygon has 4 sides
180(4-2) = 180(2) = 360 degree
80+90+2x + 3x = 360
170+5x = 360
5x = 190
x= 38
measure of angle t is 2(38)= 76
the answer is c. trust me
hope this !

Bis the correct answer