The radii of two circles are 20 cm and 13 cm, respectively. Find the radius of the circles which has a circumference equal to the sum of the circumference of the two circles.
Answer & explanation
Correct answer: option 1
We know that,
Circumference of the circle = 2πr
We have,
The radii of two circles = 20 cm and 13 cm
Let the radius of the bigger circle = R cm
then, Circumference of bigger circle = 2π R = 2π × 20 = 40π
Circumference of circle (radius = 13 cm) = 2π × 13 = 26π
According to the question = 2π R = 40π + 26π
= 2π R = 66 π
R = 33 cm