WAEC Mathematics 2024 Question 21

Question 21

Mensuration of Plane Shapes

In the diagram, MN // KL, ML and KN intersect at X. |MN| = 12 cm, |MX| = 10 cm and |KL| = 9 cm. If the area of ΔMXN is 16 cm2, calculate the area of ΔLXK.

Diagram for this question
  1. A.8 cm2
  2. B.9 cm2
  3. C.10 cm2
  4. D.12 cm2
Show the answer and explanation

Answer: B (9 cm2)

Explanation

Because MN // KL, triangles MXN and LXK are similar with scale factor 9/12 = 3/4. Areas scale by (3/4)² = 9/16, so the area is 16 × 9/16 = 9 cm².