Question

A, B & C lie on a straight line.

D, C & E lie on a different straight line.
Angle y= 107° and angle z = 56°.
Work out x

Answer 1

x = 129°

Explanation:

∠ ABD and ∠ DBC are a linear pair and sum to 180° , then

y + ∠ DBC = 180°

107° + ∠ DBC = 180° ( subtract 107° from both sides )

∠ DBC = 73°

the exterior angle of a triangle is equal to the sum of the 2 opposite interior angles , then

x = ∠ DBC + z = 73° + 56° = 129°