Question

A spool has a diameter of 3.5 cm. If a string
makes 15 turns around it, what is its length?plz ans step by step and ans should be in point.​

Answer 1

★ How to do :-

• Here, We need to find the length of the string.

• To find the length of the string , We need to find circumference/1 turn of the string.

• Then we need to multiply it with 15. As they asked the length of the string if it makes 15 turns.

Now, Let's do it !!

★ To find 1 turn of the string :-

$\implies \underline{\boxed{\sf \purple{ Circumference = \pi \times D}}}$

↬ Circumference ➩ 22/7 × 3.5cm

By simplifying, We get :

↬ Circumference ➩ 22/2

↬11 cm.

Hence, Length of one string is 11 cm.

We know that,

• Length of one string is 11cm. So, Length of 15 turns of string will be 11 multiplied with 15.

➩ 11 × 15

➩ 165cm.

Therefore, The length of the string if it makes 15 turns around the spool is 165cm.

Answer 2

Given:-

• Diameter of spool = 3.5 cm
• If a string makes 15 turns around it.

To Find:-

• Length of the string =?

Solution:-

We know that,

$\sf\fbox\red{Circumference = π ×Diameter}$

$\sf circumference = \frac{22}{7} \times 3.5cm \\ \\ \sf circumference = \frac{22}{2} \\ \\ \sf circumference = 11cm$

Hence,Length of one string is 11 cm.

We know that,

• Length of one string is 11 cm.So,Length of 15 turns of string will be 11 multiplied with 15.

$\sf \implies11 \times 15 = 165cm$

Therefore,The length of the string if it makes 15 turns around the spool is 165cm.