Question

find the ratio of the circumferences of two circles whose radii are in the ratio 4:5.​

Answer 1

Answer:

Step-by-step explanation:

Given :-

Ratio of radii of two circle = 4 : 5

To Find :-

Ratio of circumferences

Formula to be used :-

Circumference of circle = 2πr

Solution :-

Let radius of circles be x

And  Radius of 1st circle 4x

And Radius of 2nd circle 5x

Assuming circumferences, we get

Circumference of circle = 2πr

Circumference of 1st circle = 2 × π × 4x

Circumference of 2nd circle = 2 × π × 5x

Ratio of the circumferences = Circumference of 1st circle/Circumference of 2nd circle .

= 2 × π × 4x/2 × π × 5x

= 4x/5x

= 4/5

= 4 : 5

Hence, the ratio of the circumferences of two circles are 4 : 5.

Answer 2

Answer:

4 : 5

Step-by-step explanation:

2πr1 : 2πr2 = r1 : r2 = 4 : 5