Question

The area of a circle is increased by 800%. By what percent has the diameter of the circle
increased?
(A) 100%
(B) 200%
(C) 300%
(D) 600%​

Answer 1

B200% is the answer

Answer 2

200%.

Explanation - let the diameter of circle is d.

So, area will be π(d/2)^2

Now area increased by 800%.

So, new area us 800% of π(d/2)^2

= 8π(d/2)^2

=8π*(d)^2/4

= 2π(d)^2

=200% of π (d)^2