MathDB
2023 Fall Theme p4B

Source:

December 23, 2023
2023FAlLthemegeo

Problem Statement

In triangle ABCABC, AB=13AB = 13, BC=14BC = 14, and CA=15CA = 15. Let MM be the midpoint of side ABAB, GG be the centroid of ABC\triangle ABC, and EE be the foot of the altitude from AA to BCBC. Compute the area of quadrilateral GAMEGAME.
Proposed by Evin Liang
Solution. 23\boxed{23} Use coordinates with A=(0,12)A = (0,12), B=(5,0)B = (5,0), and C=(9,0)C = (-9,0). Then M=(52,6)M = \left(\dfrac{5}{2},6\right) and E=(0,0)E = (0,0). By shoelace, the area of GAMEGAME is 23\boxed{23}.