Question

the ratio of areas of circle c1 and c2 is 3:4. if the radius of circle 2 is 28 cm. what is the area of circle c1​

Answer 1

Step-by-step explanation:

area=3/4=R1/R2

3/4=r1/28

R1=28×3/4

r1=21

Answer 2

The area of circle c1 is 1848 sq. cm.

Explanation:

Area of circle = $\pi r^2$  , where r= radius of circle.

Let the radius of two circle are $r_1\ \ \&\ r_2$ respectively.

Given : The ratio of areas of circle c1 and c2 is 3:4.

$\Rightarrow\ \dfrac{\pi r_1^2}{\pi r_2^2}=\dfrac{3}{4}\\\\ \dfrac{r_1^2}{r_2^2}=\dfrac{3}{4}$

If $r_2=28$ cm  , then

$\dfrac{r_1^2}{(28)^2}=\dfrac{3}{4}\\\\ r_1^2=\dfrac{3}{4}\times(28)^2=588\\\\ r_1^2=588$

Now , Area of circle c1= $\pi r_1^2= \dfrac{22}{7}(588)=1848\ cm^2$

Hence, the area of circle c1 is 1848 sq. cm.

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