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The radius of a sector of a circle is 7 cm. If the measure of the arc of the sector is - three right angles; find the area of the sector in case.

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#### Solution

The radius of the sector of the circle, r = 7 cm

Measure of arc of the sector = θ = 3 × 90º = 270º

∴ Area of the sector = `"θ"/360` × πr^{2}

∴ Area of the sector = `270/360 × 22/7 × (7)^2`

∴ Area of the sector = `3/4 × 22 × 7`

∴ Area of the sector = `3/2 × 11 × 7`

∴ Area of the sector = `231/2`

∴ Area of the sector = 115.5 cm^{2}

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