JAMB 2010 · UTME · Q31

If the two smaller sides of a right-angled triangle are $4\text{ cm}$ and $5\text{ cm}$ , find its area.

Worked solution (try it first)

The two smaller sides of a right-angled triangle are the ones that meet at the right angle, so one is the base and the other the height.
Area $= \frac12 \times \text{base} \times \text{height}$
$= \frac12 \times 4 \times 5$
$= 10\text{ cm}^2$ , option A.