2005 AMC 12B Problems/Problem 18

Revision as of 17:20, 21 February 2010 by Fuzzy growl (talk | contribs) (Problem)

Problem

Let $A(2,2)$ and $B(7,7)$ be points in the plane. Define $R$ as the region in the first quadrant consisting of those points $C$ such that $\triangle ABC$ is an acute triangle. What is the closest integer to the area of the region $R$?

$\mathrm{(A)}\ 25     \qquad \mathrm{(B)}\ 39     \qquad \mathrm{(C)}\ 51     \qquad \mathrm{(D)}\ 60      \qquad \mathrm{(E)}\ 80$

Solution

See also