Question
The radii of two circles are 19 cm and 9 cm respectively. Find the radius of the circle which has circumference equal to the sum of the circumference of two circles.
Solution
Let the radius of the bigger circle be R cm. and radii of two smaller circles are r1and r2, then according to question.
2πR = 2πr1 + 2πr2
⇒ 2πR = 2π (19) + 2π (9)
⇒ 2πR = 2π (19 + 9)
⇒ R = 28
Hence, radius of the circle be 28 cm.
