Question

7. The radii of two spheres are in the ratio 2:5. Find the ratio between their
surface areas.​

Answer 1

Answer:

8÷3pie:20÷3pie

Step-by-step explanation:

r=2:5

Answer 2

The ratio of surface areas of two spheres=4:25

Step-by-step explanation:

Given:-

The radii of two spheres are in the ratio 2:5.

To find:-

Find the ratio between their surface areas.

Solution:-

The radii of two spheres are in the ratio 2:5

Let they be r1:r2=2:5 =>r1=2x and r2=5x

Using formula:-

Surface area of a sphere whose radius is "r" units is 4πr² sq.units

Surface area of the sphere whose radius is r1 units= 4πr1²=4π(2x)²=16πx² sq.units----(1)

Surface area of the sphere whose radius is r2 units=4πr2²=4π(5x)²=100πx² sq.units---(2)

From (1)&(2) their ratio

=>16πx²:100πx²

=>16:100

=>4:25

Answer:-

The ratio of surface areas of two spheres=4:25