JAMB 2014 · UTME · Q28

Find the value of $x$ in the figure.

Worked solution (try it first)

The angles add up to $180^\circ$ , so the third angle is $90^\circ$ .
The longest side is the hypotenuse.
At the $60^\circ$ corner, $x$ is the opposite side and the 10 cm side is the adjacent side, so $\tan60^\circ = \dfrac{x}{10}$ .
So $x = 10\tan60^\circ = 10\sqrt3$ cm, option C.