Question

8) The ratio between the radius of two circle is 5:7. Find the ratio between theis
1) circumferences
2) areas​

Answer 1

Step-by-step explanation:

The ratio between their circumference and area is 5: 7 and 25:49 respectively. Hence the ratio between their circumference and area is 5: 7 and 25:49 respectively

Answer 2

Step-by-step explanation:

(i) the ratio of the radii of circles =5:7

let radius of first circle = 5x

and radius of second circle = 7x

therefore circumference of first circle=

$2\pi \: r$

=

$2\pi \: r \times 5x =10\pi \: x$

and circumference of second circle

=

$2\pi \times 7x = 14\pi \: x$

therefore ratio between there circumferences

= 10:14 = 5: 7

Area of first circle =

$\pi \: r ^{2}$

= 22/7 × 5x × 5x = (550/7) x^2

and area of second circle=

$\pi \: r 2 ^{2}$

=22/7 × 7x ×7x = ( 1078/7) x^2

ratio between there areas

= ( 550/7) x^2 : (1078/ 7) x^2

550: 1078 (dividing by 22)

=25:49