Question

If m<1 is 68° and m<3 is (3x - 7)º, what is x?

A. 25
B. 26 1/3
C. 49
D. 140

Answer 1

C. 49.

Explanation:

The measure of the angle below <1 = 68 degrees (vertical angles).

m < 3 = 72 + 68 External angle of a triangle theorem.

m < 3 = 140

3x - 7 = 140

3x = 147

x = 49.

Answer 2

C

Explanation:

The angle at the top of the triangle is vertical to ∠ 1 and congruent

The exterior angle of a triangle is equal to the sum of the 2 opposite interior angles.

∠ 3 is an exterior angle of the triangle, then

3x - 7 = 72 + 68 = 140 ( add 7 to both sides )

3x = 147 ( divide both sides by 3 )

x = 49 → C