Question

9. If diameter of a circle is twice as large as the diameter of a smaller circle, What

is the ratio of area of larger circle to area of smaller circle?

(+2 bonus marks for no mistake in question 9, viva may be taken)

Answer 1

Step-by-step explanation:

area = pi * r^2, r = radius = diameter/2, d = diameter

area = pi * (d/2)^2 = pi * (d^2)/4 (d/2 * d/2 = (d^2)/4)

circle B --> pi * (d^2)/4

circle A (twice as large) --> pi * (2d * 2d)/4 --> pi * (4d^2)/4 --> pi * d^2

ratio circle A area to circle B area --> (d^2)/((d^2)/4)

d^2 * 4/(d^2) = 4

ratio is 4 to 1, so answer is 4:1

$hope \: it \: helps \: you \: mate...$

❣

Answer 2

Answer:

Hey Hi

Good Morning

Let the diameter of the larger circle be 56cm

then R = 28cm

and diameter of the smaller circle = 28cm(given)

then r = 14cm

then ratio of areas

(π R^2)/(π r^2)

Cancelling π

= (28 x 28)/(14 x 14)

= 4 / 1

Thus ratio of areas is 4 : 1

Hope this helps

For any doubt comment below

Regards

Rishabh Bansal