SAT Math Multiple Choice Practice Question 196: Answer and Explanation
In the figure shown, m // n. If the measure of angle 1 = 35° and , find the measure of angle 2.
Correct Answer: D
D. Because line m is parallel to line n, angle BAC equals angle 1 because they are corresponding angles. Because AB is congruent to CB, triangle ABC is an isosceles triangle. Therefore, angle BCA is the same as angle BAC, so both are 35 degrees. The angles of the triangle must total 180 degrees, so ∠2 + ∠BAC + ∠BCA = 180°, or ∠2 + 35° + 35° = 180. Subtracting, you find that angle 2 is 110 degrees.