1954 AMC 12 Problem 5

Attempt Problem 5 of the 1954 AMC 12 below, then check your answer against the professionally curated solution from LIVE by Po-Shen Loh. You can also try the full timed exam, view all 1954 AMC 12 solutions, or check the answer key.

All problems are used with official legal permission of the Mathematical Association of America (MAA).

5.

A regular hexagon is inscribed in a circle of radius 1010 inches. Its area is:
1503150\sqrt3 sq. in.
150150 sq. in.
25325\sqrt3 sq. in.
600600 sq. in.
3003300\sqrt3 sq. in.
Answer: A
Concepts:regular polygonequilateral triangletriangle area
Small hint:
An inscribed regular hexagon has side length equal to the circle’s radius
Big hint:
Divide the hexagon into six equilateral triangles of side 1010
Solution:
The hexagon consists of six equilateral triangles of side 10.10. Its area is 6(34⋅102)=1503 6\left(\frac{\sqrt3}{4}\cdot10^2\right) =150\sqrt3 square inches.
Thus, the correct answer is A.
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