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Question
A sector is cut-off from a circle of radius 21 cm the angle of sector is 120°. Find the length of its arc and its area.
Solution
Radius of circle (r) = 21 cm
𝜃 = angle subtended at centre = 120°
Length of its arc =`theta/360^@`× 2𝜋𝑟
=`120/360× 2 ×22/7× 21`
= 44 cms
Area of sector =`theta/360^@× pir^2`
=`120/360×22/7`× 21 × 21
= (22 × 21)
= 462 cm2
𝐿𝑒𝑛𝑔𝑡ℎ 𝑜𝑓 𝑎𝑟𝑐 = 44 𝑐𝑚
Area of sector = 462 cm2
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