Mathematics
Find the area of a ring whose outer and inner radii are 19 cm and 16 cm respectively.
Mensuration
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Answer
Given,
Outer radius (R) = 19 cm
Inner radius (r) = 16 cm
Area of ring = Area of big circle − Area of small circle
Area of ring = πR2 - πr2
= π(R2 - r2)
= π(192 - 162)
= π(361 - 256)
= π(105)
=
= 22 × 15
= 330 cm2.
Hence, area of the ring = 330 cm2.
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