Question

Secants ⎯⎯⎯⎯⎯⎯⎯⎯⎯ and ⎯⎯⎯⎯⎯⎯⎯⎯⎯ intersect in the exterior of a circle. ∠ measures 27.42° and the measure of DE is 73.18°. Determine the measure of BC.

Answer 1

BC = 18.34°

Explanation:

Recall: Exterior angle formed by 2 secants = ½(the difference of the measures of the intercepts arcs)

Thus:

m<BAC = ½(DE - BC)

27.42° = ½(73.18 - BC) => Substitution

Multiply both sides by 2

2*27.42 = 73.18 - BC

54.84 = 73.18 - BC

BC = 73.18 - 54.84

BC = 18.34°