Question:
The difference between the two acute angles of a right-angled triangle is $\frac{2 \pi}{5}$ radians. Express the angles in degrees.
Solution:
Given:
Difference between two acute angles of a right-angled triangle $=\frac{2 \pi}{5} \mathrm{rad}$
$\because 1 \mathrm{rad}=\left(\frac{180}{\pi}\right)^{\circ}$
$\therefore \frac{2 \pi}{5} \mathrm{rad}=\left(\frac{180}{\pi} \times \frac{2 \pi}{5}\right)^{\circ}$
$=(36 \times 2)^{\circ}$
$=72^{\circ}$