Question

Both circle Q and circle R have a central angle measuring 140°. The area of circle Q's sector is 25π m2, and the area of circle R's sector is 49π m2. Which is the ratio of the radius of circle Q to the radius of circle R?

Answer 1

The answer will be 5/7

Answer 2

Solution:

we are given that

Both circle Q and circle R have a central angle measuring 140°. The area of circle Q's sector is 25π m^2, and the area of circle R's sector is 49π m^2.

we have been asked to find the ratio of the radius of circle Q to the radius of circle R?

As we know that

Area of the sector is directly proportional to square of radius. So we can write

$Area \ \ \alpha \ \ r^2\\ \\ \Rightarrow A=kr^2\\ \\ \text{where k is some proportionality constant }\\ \\ \Rightarrow \frac{A_1}{A_2}=\frac{r_1^2}{r_2^2}\\ \\ \Rightarrow \frac{r_1^2}{r_2^2}=\frac{A_1}{A_2}\\ \\ \Rightarrow \frac{r_1^2}{r_2^2}=\frac{25 \pi}{49 \pi}\\ \\ \Rightarrow \frac{r_1}{r_2}=\sqrt{\frac{25 \pi}{49 \pi}} \\ \\ \Rightarrow \frac{r_1}{r_2}=\frac{5}{7}$