5x + 20 = 90 - a = 90 - (3x + 40)
5x + 20 = 90 - 3x - 40 = 50 - 3x
5x + 3x = 50 - 20
8x = 30
x = 30/8 = 15/4
b = 3(15/4) + 40 = 45/4 + 40 = 51.25
The measure of a supplementary angle is 180 - 51.25 = 128.75
12 is the diameter. We need the circumference which you get by multiplying 12x2 sides which = 24 which is the circumference
The answer would be 5/2q+9r+6r-20s
Explanation
We have the equation
5(1/2q+3r-4s)
which would equal
5/2q+15r-20s
so with the information
We can subtract 6r from 15r to get 9r
15r-6r=9r
+9r would be the missing piece
So we substitute it in to make the equation true.
5/2q(+9r)+6r-20s
Hope this helps or was correct
The answer is 5.1 if you're looking for s all the work is in the picture