Algebrahard · Past Paper
In a triangle ABC, angle C = 3 * angle B = 2 * (angle A + angle B). Find angle B.
A40
B20
C60
D80
✓ Correct Answer: A — 40
Let A, B, C be angles. A+B+C=180. C=3B and C=2(A+B). From C=2(A+B), A+B=C/2. Substitute into A+B+C=180: C/2 + C = 180 -> 3C/2 = 180 -> C=120. Then 3B=120 -> B=40.
Share this question