HMMT 二月 2003 · 冲刺赛 · 第 24 题
HMMT February 2003 — Guts Round — Problem 24
题目详情
- [9] Compute the radius of the inscribed circle of a triangle with sides 15, 16, and 17.
HARVARD-MIT MATHEMATICS TOURNAMENT, MARCH 15, 2003 — GUTS ROUND
英文原题
[9] Compute the radius of the inscribed circle of a triangle with sides 15, 16, and 17.
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HARVARD-MIT MATHEMATICS TOURNAMENT, MARCH 15, 2003 — GUTS ROUND
解析
英文解析
- Compute the radius of the inscribed circle of a triangle with sides 15, 16, and 17.
√
Solution: 21
√ √
Hero’s formula gives that the area is 24 · 9 · 8 · 7 = 24 21. Then, using the resultthat the area of a triangle equals the inradius times half the perimeter, we see that the
√
radius is 21. 6