Question

A string is wound symmetrically around a circular rod. The string goes exactly 4 times around the rod. The rod has circumference of 4 and a length of 12. What is the length of string? ​

Answer 1

Step-by-step explanation:

Let's look at the first loop around the rod.

If we develop the corresponding 1/4 of the cylinder, it results a rectangle whose sides are 4 and 12/4 = 3.

The diagonal is 5 (ask Pythagora why), so the length of the string is 4*5 = 20.

Answer 2

Step-by-step explanation:

Given A string is wound symmetrically around a circular rod. The string goes exactly 4 times around the rod. The rod has circumference of 4 and a length of 12. What is the length of string?

• So there is a circular rod. Also a string is wound on the rod. Now if the rod is cut as a straight line from one end of the rod to the other end and opened, it forms a rectangle when placed on a flat surface. The rectangle is 12 cm by 4 cm as shown in the diagram.
• So the rectangle is divided into four equal sized rectangles that is 3 x 4 = 12 cm
• Now we know the square on the hypotenuse is the sum of the squares on the other two sides by Pythagoras Theorem.
• So by knowing the two sides of length 3 and 4 the hypotenuse will be
•                  AC^2 = AB^2 + BC^2
•                             = 3^2 + 4^2
•                             = 9 + 16
•                             = 25
•            Or AC = 5 cm
• So the four hypotenuses put together will be the total length of the string.
• Therefore 4 x 5 = 20 cm is the length of the string.

Reference link will be

https://brainly.in/question/43709414