Answer:
s = 18
Step-by-step explanation:
A triangle's interior angles must all add up to 180 degrees.
Since you know 1 angle is 45 degrees, then the last 2 angles must equal 135 degrees.
Write the equation based on the you were told about the other 2 angles:
5s + ( 3s - 9) = 135
Solve for s:
5s + 3s - 9 = 135
Add the like variables and add 9 to both sides of the equation.
8s = 144
Divide both sides by 8
s = 18
Angle 1 = 5s = 5 x 18 = 90
Angle 2 = 3s - 9 = 3(18) - 9 = 54 - 9 = 45
