Question

Use the given figure to find the value of x in terms of y. Calculate x, if y = 15°.

Answer 1

(2x - y)° = (x + 5)° + (2y + 25)°      ....(Exterior angle property)
⇒ 2x° - y° = x° + 5° + 2y° + 25°
⇒ 2x° - x° = 2y° + y° + 30°
⇒ x° = 3y° + 30°
When y = 15, we have
x° = 3 x 15° + 30° = 45° + 30° = 75°.