Answer:
x = 30
Step-by-step explanation:
A triangle's angles add up to 180
Also, angles on a straight line add up to 180
180-100 = 80
80+70=150
180-150=30
The exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.
100° is an exterior angle of the triangle, then
x + 70 = 100 ( subtract 70 from both sides )
