## Elementary Geometry for College Students (7th Edition) Clone

$\angle$1 + $\angle$2 = $90$ hence proved
Sum of angles of a triangle = $180^{\circ}$ $\angle$1 + $\angle$2 + $\angle$c = 180 given $\angle$c = 90 $\angle$1 + $\angle$2 + 90 = 180 $\angle$1 + $\angle$2 = $90$ hence proved