Geometry Problem 1276

Elements: Equilateral Triangle, Circumcircle, Internally Tangent Circles, Tangent Line, Measurement

Circles O and O1 are tangent internally at T, as shown in the figure. An equilateral triangle ABC is inscribed in the larger circle O so that T is on the arc BC. If AA1, BB1, and CC1 are tangent to the circle O1, prove that AA1 = BB1 +CC1.


Geometry Problem 1276: Equilateral Triangle, Circumcircle, Internally Tangent Circles, Tangent Line, Measurement

See also:
Geometry problem 1271 in motion