Question 411558
You're at a good start. Now it's simply an algebra problem. Collect the x terms, then collect the constant terms to obtain


180 = (x+16) + (x+35) + (x+21)


180 = 3x + 72. Subtract 72 from both sides:


108 = 3x, divide both sides by 3 to get x = 36. However, finding the value of x alone is not sufficient since we want the angle measures, so we substitute x into our angles:


x+16 = 36 + 16 = 52 (degrees)
x+21 = 57
x+35 = 71