443

Part of 1987 All Soviet Union Mathematical Olympiad

Problems(1)

ASU 443 All Soviet Union MO 1987 r. heptagon 1/A_1A_5+1/A_1A_3=1/A_1A_7

Source:

Given a regular heptagon

A_1...A_7

\frac{1}{|A_1A_5|} + \frac{1}{|A_1A_3| }= \frac{1}{|A_1A_7|}

Heptagongeometry