Question

In circle F what is the measure of arc CB?

17.5
35
70
60

Answer 1

measure of arc CB is 70°

Explanation:

Draw segment FC.

Measure of arc CB = ∠CFB

∠CFB is complementary to ∠CFA

∠CFB = 180° - ∠CFA

Δ CFA is isosceles

∠ FAC = ∠ FCA = 35°

∠CFA +∠ FAC + ∠ FCA = 180°

∠CFA = 180° - 70°

∠CFB = 180° - (180° - 70°) = 70°

∴ Measure of arc CB is 70°

Answer 2

Multiply by 2 to get that the measure of arc CB is 70.