Question

The length of a rectangular field is 20 m more than its breadth.If the perimeter of the field is 280 m, what is its length?

Answer 1

l = b+20
perimeter = 2(l+b)
= 2(b+20+b)
= 2(2b+20)
= 4b +40 = 280
4b = 240
b= 60m
l = 60+20= 80m

Answer 2

Answer:

80 m

Step-by-step explanation:

Given : The length of a rectangular field is 20 m more than its breadth.

To Find: .If the perimeter of the field is 280 m, what is its length?

Solution:

Let the breadth of rectangle be x

Since we are given that length of a rectangular field is 20 m more than its breadth.

So, Length = 20+x

Formula of perimeter of rectangle = $2(Length\times Breadth)$

Now we are given that  the perimeter of the field is 280 m

So, $280=2(20+x+x)$

$280=2(20+2x)$

$280=40+4x$

$240=4x$

$60=x$

So,breadth = 60m

Length = 20+x=20+60=80 m.

Hence the length of the rectangle is 80 m