返回题库

HMMT 十一月 2012 · 冲刺赛 · 第 3 题

HMMT November 2012 — Guts Round — Problem 3

专题
Discrete Math / 离散数学
难度
L3
来源
HMMT

题目详情

  1. [ 5 ] Find the area of the region between two concentric circles that have radii 100 and 99. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . HMMT NOVEMBER 2012, 10 NOVEMBER 2012 — GUTS ROUND ◦ ◦ ◦
解析
  1. [ 5 ] 2 2 Answer: 199 π The area of a circle of radius 100 is 100 π , and the area of a circle of radius 99 is 99 π . 2 2 Therefore, the area of the region between them is (100 − 99 ) π = (100 + 99)(100 − 99) π = 199 π .