## Trigonometry (10th Edition)

$\theta$ = 35$^{\circ}$
$\csc$($\theta$ + 40$^{\circ}$) = $\sec$($\theta$ - 20$^{\circ}$) $\sin$ and $\cos$ are cofunctions of each other assuming that the sum of the angles equals 90$^{\circ}$ ($\theta$ + 40$^{\circ}$) + ($\theta$ - 20$^{\circ}$) = 90$^{\circ}$ 2$\theta$ + 20$^{\circ}$ = 90$^{\circ}$ 2$\theta$ = 70$^{\circ}$ $\theta$ = 35$^{\circ}$