Question

What measure of angle should be subtracted from an obtuse angle that will always result in an acute angle?

degrees

Answer 1

An obtuse angle is an angle that is more than ${90}^o$ and less than ${180}^o.$
Let an obtuse angle be $x.$
Hence, it can be expressed as $x={90}^o+c$, where $c$ is less than ${90}^o$ but greater than $0^o.$

$\Rightarrow c=x-{90}^o$

Hence, by subtracting ${90}^o$ from any obtuse angle $x$, the resulting angle is always acute ($c$).

For example, consider the obtuse angle ${179}^o.$
$\to {179}^o-{90}^o={89}^o$
${89}^o$ is an acute angle.