Answer:
3x+15=90.
3x=75
x=25
Step-by-step explanation:
x = 25
Triangle = 180 degrees
The square indicates that the angle = 90 degrees
So we know the other two angles have to equal the remaining 90 together.
x + (2x + 15) = 90
3x + 15 = 90
3x = 75
