Question

If A ABC ~ ARST and m 2 A = 42°, m 2 C = 60°,
find the measure of < S.

Answer 1

78

Explanation:

∠A + ∠B + ∠C = 180 { Angle sum property of triangle}

42 + ∠B + 60 = 180

∠B + 102 = 180

∠B = 180 - 102 = 78

In similar triangles, corresponding angles are congruent.

∠S ≅ ∠B

∠S = 78°