Question

Triangle ABC has angle measures as shown.

Answer 1

As with any triangle, the sum of angles is 180°.

(a)
(x -5) +(3x +30) +35 = 180 . . . . . sum of angles is 180
4x +60 = 180 . . . . . . . . . . . . . . . . collect terms
4x = 120 . . . . . . . . . . . . . . . . . . . . subtract 60
x = 30 . . . . . . . . . . . . . . . . . . . . . . divide by 4


(b)
Angle A = x -5 = 30 -5 = 25

Angle B = 3x +30 = 3*30 +30 = 120