Question

The ratio of radii of two circles is 4:5. Find the ratio of their areas

Answer 1

Answer:

If the ratio of radii of two circles is 4:5, then the ratio of their areas is 16: 25.

Step-by-step explanation:

Given :

The ratio of radii of two circles is 4:5

Find: The ratio of their areas

Formula: Area of circle = $\pi r^{2}$

If the common multiple is x then the radii of circles are 4x and 5x

The ratio of their areas

$\frac{\pi r_1^2 }{\pi r_2^2} \\= \frac{ r_1^2 }{ r_2^2}\\= \frac{ (4x)^2 }{ (5x)^2}\\=\frac{16}{25}$

Answer 2

Answer :

• Area are in the ratio is 16:25.

Given :

• The ratio of radii of two circles is 4:5

To find :

• Ratio of their areas

Solution :

Given,

The ratio of radii of two circles is 4 : 5 then,

• Let the radii of first ratio be 4x
• let the radii of second ratio be 5x

As we know that

• Area of circle = πr²

Where,

• r is radius

↦ π(4)² : π(5)²

↦ 16x² π : 25x² π

Now remove x² and π we get,

↦ 16 : 25

Hence,

Area are in the ratio is 16:25.