Question

In a circle of radius 21cm, an arc subtends an angle of 60 at the

centre. Find the area of the sector formed by the arc.​

Answer 1

$\theta = 60 \degree$

$\frac{ \theta}{360 \degree} \times \pi \: {r}^{2}$

$= \frac{60}{360} \times 3.14 \times {(21)}^{2} \\ \\ = \frac{1}{6} \times 3.14 \times 441 \\ \\ = 0.52 \times 441 \\ = 229.32 {cm}^{2}$

Area of sector = 229.32 ≈ 230 cm²

Answer 2

$\huge{\bf{\green{\mathfrak{\dag{\underline{\underline{Answer:-}}}}}}}$

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$\sf\red{To\: Find:\:}$

$\sf\green{The\: area\: of\: the\: sector\: formed\: by\: the\: arc\:}$

⟹ $\sf{Area\: of\: the\: sector\: OAPB\:}$

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$= \sf \frac{θ}{360} \times \pi \: r {}^{2}$

$= \sf\frac{60}{360 } \times \frac{22}{7} \times 21 \times 21$

$= \sf\frac{1}{6 } \times \frac{22}{7} \times 21 \times 21$

$= \sf \frac{1}{6} \times 22 \times 3 \times 21$

$\fbox\pink{231cm²\:}$

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