MathDB
2023 CUBRMC Team #2 area of concave decagon

Source:

March 8, 2024
geometrycubrmc

Problem Statement

The concave decagon shown below is embedded in the Cartesian coordinate plane such that all of its vertices have integer coordinates. Two opposite edges have length 55, whereas the remaining eight edges have length 10\sqrt{10}. Every pair of opposite edges is parallel. The sides of the decagon do not intersect each other, and the decagon has vertical and horizontal axes of symmetry. Find the area of the decagon. https://cdn.artofproblemsolving.com/attachments/1/5/daa4ab3d71af4b3274cd222f9a091eea3be705.png