Answer:
90
Step-by-step explanation:
The sum of the angles is 360 degrees since this is a quadrilateral
x+2x+80+145 = 360
Combine like terms
3x +225 = 360
Subtract 225 from each side
3x+225-225 = 360-225
3x =135
Divide each side by 3
3x/3 = 135/3
x =45
We want to find angle S
S = 2x = 2(45) = 90
