WAEC Mathematics 2010 Question 42

Question 42

Mensuration of Plane Shapes

The diagram shows a rectangular cardboard from which a semi-circle is cut off. Calculate the area of the remaining part.

Diagram for this question
  1. A.44 cm2
  2. B.99 cm2
  3. C.154 cm2
  4. D.165 cm2
Show the answer and explanation

Answer: B (99 cm2)

Explanation

Rectangle = 22 × 8 = 176 cm2. Semicircle diameter = 22 − 4 − 4 = 14 cm, so area = ½ × 22/7 × 72 = 77 cm2. Remaining = 99 cm2.