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

$x=45^{\circ}$ $y= 45^{\circ}$
$m\angle 3$ = $90^{\circ}+m\angle1$ Putting given values $3x= 90^{\circ} + x$ $x=45^{\circ}$.............................Eq1 Now in $\triangle ABC$ $m\angle 1+ m\angle 2 = 90^{\circ}$ putting values $x+y= 90^{\circ}$................Eq2 putting value of $x$ from Eq1 in Eq2 $y$= $45^{\circ}$