Lines ab and ac tangent to circle k(o) at b and c respectively. find bc, if m∠oab=30°, and ab=5 cm.

5 cm

Step-by-step explanation:

ΔABC is equilateral, so BC = AB = 5 cm.

AO is the perpendicular bisector of BC and the angle bisector of angle A, so ∠OAC = ∠OAB = 30°. Then vertex angle BAC of isosceles triangle ABC is 60°, which means all angles in the triangle are 60° and the triangle is equilateral.

b

step-by-step explanation:

the answer is 8/21

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