# How do you find the exact value of the third side given triangle PQR, p=126, q=214, mangleR=42?

Mar 12, 2017

$r \cong 146 , 95$
$r = \sqrt{{p}^{2} + {q}^{2} - 2 p q \cos \hat{R}}$
=sqrt(126^2+214^2-2*126*214*cos42°)~=146,95