Proof Hexagon: Hey, I'm a German 11th grader and we currently have a tough geometry question: The centers A, B, C of three congruent circles that have no common points do not lie on the same straight line. From points A, B, C, the six tangents shown in the figure are placed on the circles that enclose a convex hexagon. Prove: The sums of the lengths of three pairs of not immediately adjacent sides of this hexagon are equal, i. e. | PQ | + | RS | + | TU | = | QR | + | ST | + | UP |
How can I prove this? I already found out that the triangles on the sides of the hexagon are not pairwisely congruent, as i first thought. I think my other idea that the red and orange triangles (attachment) are congruent, so the sum of the areas of the triangles on the above mentioned sides is equal, but the congruency of red and orange must be proven too. Any help is appreciated!