Question

An angle which is four times its complement. Find the angle.

Answer 1

Let the angle be x degrees
It's compliment = 90-x
As per question,
x = 4(90-x)
$\Rightarrow$ x = 360 - 4x
$\Rightarrow$ x+4x = 360
$\Rightarrow$ 5x = 360
$\Rightarrow x=\frac{360}{5}$ = 72 degrees.
Compliment of 72 degrees = 90-72 = 18 degrees
72 is 4 times 18. So, it is correct.