Question

Find the area of the shaded portion:


[4 marks]

Answer 1

To find the area of EFDC, first we have to find the area of ΔAEF, ΔEBC and rectangle ABCD

Area of ΔAEF = $\frac{1}{2}$× Base × Height
= $\frac{1}{2}$ × 6 × 10
= 1 × 3 × 10
= 30 cm² (1 mark)

Area of ΔEBC = $\frac{1}{2}$× Base × Height
= $\frac{1}{2}$ × 8 × 10
= 1 × 4 × 10
= 40 cm² (1 mark)

Area of rectangle ABCD = length × breadth
= 18 × 10
= 180 cm² (1 mark)

^Then,
Area of EFDC = Area of ABCD – (ΔAEF + ΔEBC)
= 180 – (30 + 40)
= 180 – 70
= 110 cm² (1 mark)