I need help with math it is in the description

Question

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A rope wraps around the barrel as shown. Approximately 20 additional centimeters of the rope are used to tie the knot.

What is the approximate total length of the rope in centimeters?

Answer 1

Suppose there was no knot. Do you know how to find the circumference of a circle? That is the amount of rope required to go around the barrel.

C = 2πr, where r is the radius of the circle. Since the diameter shows as 90 cm, the radius is 45 cm.

Determine the value of C as 2(π)45. Since the question asks for an approximate length you can use 3.14 for π.

Once you have that calculation, add 20 cm (for the knot) to get the total length of rope.