Question

10) Given that two tangent lines are constructed from the shared point A outside a circle with the center O and points of tangency B and C, what is the relationship between ∠OAB and ∠OAC?

Answer 1

Those two angles are congruent.

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The angles are corresponding parts of congruent triangles (CPCT). Triangles OBA and OCA are right triangles congruent by the HL postulate. The "H" is segment OA. The "L" is the radius, OB or OC. Of course the angles at B and C are 90° as with any radius and tangent line.