Question

Sarika is the owner of a square shaped plot of total area 140 sq. m. She wants to put a fence around it for safety purpose. How much wire does she require for the fencing?
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Answer 1

Step-by-step explanation:

$\sf \large \: Solution$

Here, we must find the length of the side of the plot.

Sarika wants to know the approximate length so that she can find out how much wire she has to buy for fencing.

$\sf \: Here, \sqrt{140} \: will \: give \: us \: the \: length \: \\ \sf of \: the \: side \: of \: the \: square.$

Many times we need to know the approximate square root.

Let us see how to quickly make an estimate of the square root of the given number. Identify the nearest square numbers to 140.

They are 121 and 144.

$\sf \: We \: know \: that \: 11^ 2 \\ \sf =121<140<12^ 2 =144 . \\ \sf\Rightarrow11< \sqrt {140} <12$

Observe that 140 is much closer to 144 than it is to 121.

$\sf \therefore \sqrt{140} \: is \: approximately \: 12.$

The length of the wire required for fencing

$\sf=4 \times 12=48 m \: approximately.$