Question

OACB is a quadrant of a circle with centre O and radius 7 cm. It OD = 4cm, then find area of shaded region.

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Answer 1

Area of quadrant OACB = $\frac{90}{360}$ $\pi$ × $7^2$ = $\frac{77}{2}$

Area of shaded region = Area of quadrant OACB - area of $\Delta$OAD

= $\frac{77}{2}$ - $\frac{1}{2}$ × 7 × 4

= 24.5 $c{m}^2$