Olympiad Maths Prep

Track / Stage 4 / 61 of 340 #321 of 2000

Problem 321

AMC 12 late, AIME early
Geometry Difficulty 4.6 Find the answer

31. In a convex pentagon ABCDEA B C D E, all sides are equal, and the angle ACEA C E is half the angle BCDB C D. Find the angle ACEA C E.

Official solution

76.31. Answer. 3030^{\circ}. Hint. Apply to the given pentagon a triangle CDAC D A^{\prime}, equal to triangle CBAC B A.

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