Ex.11.1 Q3 Perimeter and Area - NCERT Maths Class 7

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Question

Find the breadth of a rectangular plot of land, if its area is \(440 \,\rm{m^2}\) and the length is \(22 \,\rm{}m.\) Also, find its perimeter.

Text Solution

 

What is known?

Area and length of rectangular plot of land.

What is unknown?

The breadth of a rectangular plot and its perimeter.

Reasoning:

This question is based on the concept of area and perimeter of rectangle.using the formula of area of rectangle, find the breadth of rectangular plot. Now,the length and breadth of the rectangular plot is known, use the formula of perimeter of rectangle and find the perimeter of plot of land.

Steps:

Area of rectangular plot of land \(= 440 \,\rm{m^2}\)

Length of rectangular plot of land \(= 22 \,\rm{}m\)

Let us say that breadth of rectangular plot of land \(= x \,\rm{}m\)

We know that,

\[\begin{align}\text{Area of rectangle}&= {\rm{Length}} \times {\rm{Breadth}}\\{\rm{440}} &= {\rm{22}}\,x\\x &= \frac{{440}}{{22}}\\x &= 20\;m\end{align}\]

So, breadth of rectangular plot of land \(= 20 \,\rm{}m\)

\[\begin{align}\text{Perimeter of a rectangle} &= 2\left( {{\rm{Length}} + {\rm{Breadth}}} \right)\\&= 2\left( {22 + 20} \right)\\ &= 84{\,\rm{ m}}\end{align}\]

  
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