Question

Find the area and perimeter of the following sector :

Diameter = 42 cm, angle at the centre is 100·. 

Answer 1

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