The areas of two concentric circles are 1386 cm2 and 962.5 cm2. The width of the ring is

Let the radius of circle 1 & 2 be R1 and R2 respectively


Area of circle 1 = 1386 cm2


= 1386 cm2


22/7 × = 1386 cm2


1386 × 7/22 cm2 = 441 cm2


R1 = 21 cm


Area of circle 2 = 962.5 cm2


π = 962.5 cm2


22/7 × = 962.5 cm2


962.5 × 7/22 cm2 = 306.25 cm2


R2 = 17.5 cm


Width of the ring = R1 – R2 = 21 -17.5 = 3.5 cm

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