NECO 2023 · Paper 1 · Q36

In the figures, the two right-angled triangles have equal marked angles. Find the value of $L$ in metres.

Worked solution (try it first)

The triangles have equal angles, so they are similar and their matching sides are in the same ratio.
$L$ and 18 cm are the vertical sides.
420 m and 24 cm are the bases.
So $\dfrac{L}{420} = \dfrac{18}{24}$ .
Multiply by 420: $L = 420 \times \frac34 = 315$ m, option E.