Question 33

The area of a circle got increased by 22 cm when the radius was increased by 1 cm. What was the original radius?

Solution

area of circle = $$\pi\times r^2$$

radius = r

ATQ

$$\pi(r + 1)^2- \pi\times r^2 = 22$$

$$\pi((r + 1)^2- r^2) = 22$$

$$\frac{1+ 2r}{7}=1$$

2r = 6

r = 3cm


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