In the figure (i) given below, AOBC is a quadrant of a circle of radius 10 m. Calculate the area of the shaded portion. Take π = 3.14 and give your answer correct to two significant figures.

Area of quadrant = $\dfrac{πr^2}{4}$

$= \dfrac{3.14 \times 10^2}{4} \\[1em] = \dfrac{314}{4} \\[1em] = 78.5 \text{ m}^2.$

Area of triangle AOB = $\dfrac{1}{2} \times OB \times AO$

$= \dfrac{1}{2} \times 10 \times 10 \\[1em] = \dfrac{1}{2} \times 100 \\[1em] = 50 \text{ m}^2$

Area of shaded region = Area of quadrant - Area of triangle

= 78.5 - 50

= 28.5 ≈ 29 m².

Hence, area of shaded region = 29 m².