Prove that the tangents drawn to a circle from an external point are congruent. Good luck!
Let the external point = C
Let the tangent points be A and B
Let the circle center = 0
Draw OC, OA and OB
And we have two triangles OCA and OCB
Now OA and OB are radii drawn to tangent points......so they meet the tangents at right angles
And OA = OB since they are radii
And CO = CO
So....CO is the hypotenuse of two right triangles
And OA and OB are equal legs
So...by Hypotenuse - Leg, the other two legs of both triangles - CA and CB - are equal
But.....CA and CB are the tangents drawn from C
So.....they are equal