Question:
Find the angle whose complement is one-third of its supplement.
Solution:
Let the measure of the required angle be $x^{\circ}$
Then, the measure of its complement $=(90-x)^{\circ}$.
And the measure of its supplement $=(180-x)^{\circ}$.
Therefore,
$(90-x)=\frac{1}{3}(180-x)$
$\Rightarrow 3(90-x)=(180-x)$
$\Rightarrow 270-3 x=180-x$
$\Rightarrow 2 x=90$
$\Rightarrow x=45$
Hence, the measure of the required angle is $45^{\circ}$.