Answer
$\theta$ = 35$^{\circ}$
Work Step by Step
$\sin$($\theta$ - 20$^{\circ}$) = $\cos$(2$\theta$ + 5$^{\circ}$)
$\sin$ and $\cos$ are cofunctions if the sum of the angles is 90$^{\circ}$
Therefore:
($\theta$ - 20$^{\circ}$) + (2$\theta$ + 5$^{\circ}$) = 90$^{\circ}$
3$\theta$ - 15$^{\circ}$ = 90$^{\circ}$
3$\theta$ = 105$^{\circ}$
$\theta$ = 35$^{\circ}$
