Question

If m∠1 = 3x, m∠3 = 2x + 20 and m∠5 = 30, what is the value of x?

Answer 1

M∠2 = 180 - m∠1 = 180 - 3x   [supplementary angles]

In a triangle, the three interior angles always add to 180° ⇒
m∠2 + m∠3 + m∠5 = 180
180-3x + 2x+20 + 30 = 180
230 - x = 180
x = 230 - 180
x = 50