Question

"Question 1 A square and a rectangular field with measurements as given in the figure have the same perimeter. Which field has a larger area?

Class 8 Mensuration Page 171"

Answer 1

First let us find out the perimeter of the square.
P=S×4
P=60×4
P=240m
Now the length of one sside of figure b has been given. We know that the opposite sidw is also equal.
We know that:
80×2+2x=240
=>160+2x=240
=>2x=240-160
=>x=80/2
=>x=40m

Now area of square=60×60sq.m
=3600sq.m

Now area of rectangle
=l×b
=80×40
=3200sq.m

So, area of square is bigger

Answer 2

Mensuration:

Mensuration is the branch of mathematics which concerns itself with the measurement of Lengths, areas & volume of different geometrical shapes or figures.

Plane Figure: A figure which lies in a plane is called a plane figure.

For e.g:  a rectangle, square, a rhombus, a parallelogram, a trapezium.

 

Perimeter:

The perimeter of a closed plane figure is the total length of its boundary.

In case of a triangle or a polygon the perimeter is  the sum of the length of its sides.

Unit of perimeter is a centimetre  (cm), metre(m) kilometre(km) e.t.c

Area: The area of the plane figure is the measure of the surface enclose by its boundary.

 

The area of a triangle are a polygon is the measure of the surface enclosed by its sides.

A square centimetre (cm²) is generally taken at the standard unit of an area. We use square metre (m²) also for the units of area.

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Solution:

Answer is in the attachment..

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Hope this will help you...