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Question
Find the area and perimeter of the following sector :
Diameter = 42 cm, angle at the centre is 100·.
Solution
Diameter= 2r
`=> "r" = "diameter" /2 = 42/2 = 21 "cm"`
Area of the sector = `(pi "r"^2 xx theta/360^circ)`
`= 22/7 xx 21 xx 21 xx 100^circ/360^circ`
= 385 cm2
Peri meter of the sector = `2"r" + (2 pi "r" xx theta /360^circ)`
`= 2 xx 21 + (2 xx 22/7 xx 21 xx 100^circ/360^circ)`
= 42 + 36.66
= 78.66 cm
Area of the sector = 385 cm2 and perimeter = 78.66 cm
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