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Italian MO 2017 P1

Source: Italian MO 2017 P1

May 6, 2017
geometryrectangle

Problem Statement

Let aa and bb be positive real numbers. Consider a regular hexagon of side aa, and build externally on its sides six rectangles of sides aa and bb. The new twelve vertices lie on a circle. Now repeat the same construction, but this time exchanging the roles of aa and bb; namely; we start with a regular hexagon of side bb and we build externally on its sides six rectangles of sides aa and bb. The new twelve vertices lie on another circle. Show that the two circles have the same radius.