Question

9. The ratio of the circumference of two circles is 4: 1. Find the ratio of their areas. find the radius and the area of the circle. ​

Answer 1

$c_{1} \: : c_{2} = 4 : 1$

$2\pi \: r_{1} \ \: : 2\pi \: r_{2} = 4 \ \: : 1$

$r_{1} \ : \: r_{2} = 4 \: : 1$

$\frac{A _{1}}{A _{2}} = \frac{\pi \: r \frac{2}{1} }{\pi \: r \frac{2}{2} } = \frac{ { {4}^{2} } }{ {1}^{2} } = \frac{16}{1}$

$∴A _{1} ; A _{2} = 4 \ \: : 1$

Answer 2

Step-by-step explanation:

$c_{1} \: : c_{2} = 4 : 1c1:c2=4:1</p><p></p><p>2\pi \: r_{1} \ \: : 2\pi \: r_{2} = 4 \ \: : 12πr1 :2πr2=4 :1</p><p></p><p>r_{1} \ : \: r_{2} = 4 \: : 1r1 :r2=4:1</p><p></p><p>\frac{A _{1}}{A _{2}} = \frac{\pi \: r \frac{2}{1} }{\pi \: r \frac{2}{2} } = \frac{ { {4}^{2} } }{ {1}^{2} } = \frac{16}{1}A2A1=πr22πr12=1242=116</p><p></p><p>∴A _{1} ; A _{2} = 4 \ \: : 1∴A1;A2=4 :1</p><p></p><p>$