SOLUTION: Seven hard plastic tubes of radius 2 cm are tied tightly together.If the string is wound around twice and a 5 cm piece is needed for tying the knot,how much string is needed?

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Question 631784: Seven hard plastic tubes of radius 2 cm are tied tightly together.If the string is wound around twice and a 5 cm piece is needed for tying the knot,how much string is needed?
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
Here is a cross section of the bundle of tubes, tied with a red string:
The radius is 2 cm for the small circles, 6 cm for the large, red one.
The length (in highlight%28cm%29) of string needed is 2 times the circumference of the red circle plus:
2%2A%282%2Api%2A6%29%2B5=24%2Api%2B5=highlight%2880.4%29 cm (rounded to the millimeter).