Three circles of radius 7 cm are kept touching each other. The string is tightly tied around these three circles. What is the length of the string?
Answer & explanation
Correct answer: option 3
Three circles’s radius = 7 cm
We know that,
Circumference of circle = 2πr
According to the question,
The length of the string not in contact with the circle,
= 2r + 2r + 2r = 6r = 6 × 7 = 42
The angle of the made by string on one circle = 120o
Length of string touching circle,
\(\frac{2πг }{3}\) + \(\frac{2πг }{3}\) + \(\frac{2πг }{3}\) = 2πr
= 2 × 7 × π = 14π
Total length = 42 + 14π.