# How would you figure out if a triangle with vertices (0,5), (1,2.5), and (-10,1) is a right triangle?

Nov 10, 2015

Slope of AC: $a = \frac{5 - 1}{0 + 10} = \frac{4}{10} = \frac{1}{2.5}$
Slope of line AB: $b = \frac{5 - 2.5}{0 - 1} = \frac{2.5}{-} 1 = - 2.5$