Q. 85.0( 1 Vote )
The radius of a
Let the radius of the circle be r units.
We know that,
Area of the circle of radius r = πr 2
Since, The radius of the circle when it is doubled = 2r
⇒ Area of the circle when the radius is doubled = π(2r) 2
= 4πr 2
⇒ The ratio of the areas of the new circle to the given circle
= 4πr 2 : πr 2
= 4 : 1
The area increases by 4 times as the radius of circle is doubled.
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