Question

The radil of two circles are 13cm and 6cm respectively. The radius of the circle which has circumference equal to sum of the circumference of the two circles is

Answer 1

Answer

The radius of the circle which has circumference equal to sum of the circumference of the two circles is 19cm

Solution

circumference  of circle with radius r is 2πr

To find the circumference  of circle with radius 13cm

circumference  of circle =2 x π x 13=26π

To find the circumference  of circle with radius 6cm

circumference  of circle =2 x π x6=12π

sum of the circumference of the two circles is = 26π +12π = 38π

The circumference of the circle which has circumference equal to sum these two circle

2πr = 38π

r=38/2 =19cm

Answer 2

Circumference of the circle with radius 13 cm

Circumference = 2πr

Circumference = 2π(13) =26π cm

Circumference of the circle with radius 6 cm

Circumference = 2πr

Circumference = 2π(6) =12 π cm

Sum of the circumference

Circumference = 26π  + 12π = 38π cm

Find the radius

Circumference = 2πr

38π = 2πr

r = 38π ÷ 2π = 19 cm

Answer: The radius is 19 cm