Answer:
138
Step-by-step explanation:
Theorem:
The measure of an exterior angle of a triangle is equal to the sum of the measures of its remote interior angles.
Let's examine the given triangle. Angle x is an exterior angle. <BAC is an interior angle of the triangle. <x and <BAC are adjacent angles. Angles B and C are not adjacent to <x. "Remote" means far away. Of all interior angles of triangle ABC, angles B and C are the remote interior angles of exterior angle x.
Now look at the theorem above. It states that the measure of any exterior angle of a triangle equals the sum of the measures of its remote interior angles.
In this case, <x is an exterior angle. Its remote interior angles are angles B and C. The measure of <x is equal to the sum of the measure of angles B and C.
m<x = m<B + m<C
m<x = 68° + 70°
x = 138
