Question

please help me with this....​

Answer 1

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→Given;

•Circumference of two circle are in ratio of 4:5.

We know that

→Circumference[C]=2πr

→$\frac{{C}_{1}}{{C}_{2}}$=$\frac{4}{5}$

→2π${r}_{1}$=2π${r}_{2}$

→$\cancel{2π}$${r}_{1}$=$\cancel{2π}$${r}_{2}$

→${r}_{1}$=${r}_{2}$

→$\frac{{r}_{1}}{{r}_{2}}$=$\frac{4}{5}$

Thus the ratio of their radius is 4:5

•Now the ratio of their area

We know the area of circle =πr²

→π${r}_{1}$²=π${r}_{2}$²

→${r}_{1}$²=${r}_{2}$²

→4²=5²

→16=25

→4=5

Thus the ratio of its area is 4:5