Question 30

If the radius of a circle is increased to twice its original length, how much will the area of the circle increase?

(a) 1.4 times
(b) 2 times
(c) 3 times
(d) 4 times

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Solution

Let r be the radius of the circle.
$∴$ Area of circle $= π r^{2}$
If the radius is increased to twice its original length, then radius will be 2r.
Now, area of new circle $= π (2 r)^{2} = 4 π r^{2} = 4$ times of original area
Hence, the area of the circle will be increased to 4 times.

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Question 30 If the radius of a circle is increased to twice its original length, how much will the area of the circle increase? (a) 1.4 times (b) 2 times (c) 3 times (d) 4 times

Let r be the radius of the circle. ∴ Area of circle =πr2 If the radius is increased to twice its original length, then radius will be 2r. Now, area of new circle =π(2r)2=4πr2=4 times of original area Hence, the area of the circle will be increased to 4 times.

Question 30

If the radius of a circle is increased to twice its original length, how much will the area of the circle increase?

(a) 1.4 times
(b) 2 times
(c) 3 times
(d) 4 times

Let r be the radius of the circle.
$∴$ Area of circle $= π r^{2}$
If the radius is increased to twice its original length, then radius will be 2r.
Now, area of new circle $= π (2 r)^{2} = 4 π r^{2} = 4$ times of original area
Hence, the area of the circle will be increased to 4 times.