Question
When the radius of a circle is increased by 1 cm, its
area increases by 22 cm². What was the original radius of the circle?Solution
Let the radius of the circle be r cm new radius of the circle = (r + 1) As we know, Area of the circle = πr² According to the question - π (r + 1) ² – πr² = 22 π [ r+ 1)2-r2] = 22  (22/7) [r² + 1 + 2r - r² ] = 22  (1 + 2r) = 7 2r = 7-1 r = 6/2 r = 3 cm.
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