# Ex.11.3 Q17 Perimeter and Area - NCERT Maths Class 7

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## Question

The minute hand of a circular clock is $$15 \rm\,cm$$ long. How far does the tip of the minute hand move in $$1$$ hour? (Take $$π = 3.14$$)

Video Solution
Perimeter And Area
Ex 11.3 | Question 17

## Text Solution

What is known?

The minute hand of a circular clock is $$15 \rm\,cm$$ long.

What is unknown?

Distance covered by tip of minute hand in $$1$$ hour.

Reasoning:

In one hour, the minute hand completes one full circle. So, the distance covered by tip is equal to the circumference of the circle.

Steps:

Radius of the circle $$(r) =$$ $$15 \rm\,cm$$

Circumference of circular clock

\begin{align} &= 2\pi r \\ &= 2 \times 3.14 \times 15\\ &= {\rm{ }}94.2{\rm{ }}\rm\,cm\end{align}

Therefore, the tip of the minute hand moves $$94.2 \rm\,cm$$ in $$1$$ hour.

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