The length of a rectangular field is thrice its breadth, if it's perimeter is 400 then find its length and breadth? 

Asked by ameetjain75 | 9th Mar, 2017, 10:13: PM

Expert Answer:

begin mathsize 16px style Let space the space breadth space of space the space rectangle space be space straight x
So comma space the space length space equals space 3 straight x
Perimeter space equals space 400 space left parenthesis Given right parenthesis
We space know space that comma space perimeter space of space straight a space rectangle equals 2 left parenthesis length plus breadth right parenthesis
rightwards double arrow space 400 equals 2 left parenthesis length plus breadth right parenthesis
rightwards double arrow space 400 equals 2 left parenthesis 3 straight x plus straight x right parenthesis
rightwards double arrow space 400 equals 2 left parenthesis 4 straight x right parenthesis
rightwards double arrow space 400 equals 8 straight x
rightwards double arrow space 8 straight x equals 400
rightwards double arrow straight x equals 400 over 8
rightwards double arrow straight x equals 50
So comma space the space breadth space equals space straight x space equals space 50 space units space
and space the space length equals 3 straight x space equals space 3 left parenthesis 50 right parenthesis equals 150 space units end stylebegin mathsize 16px style Let space the space breadth space of space the space rectangle space be space straight x
So comma space the space length space equals space 3 straight x
Perimeter space equals space 400 space left parenthesis Given right parenthesis
We space know space that comma space perimeter space of space straight a space rectangle equals 2 left parenthesis length plus breadth right parenthesis
rightwards double arrow space 400 equals 2 left parenthesis length plus breadth right parenthesis
rightwards double arrow space 400 equals 2 left parenthesis 3 straight x plus straight x right parenthesis
rightwards double arrow space 400 equals 2 left parenthesis 4 straight x right parenthesis
rightwards double arrow space 400 equals 8 straight x
rightwards double arrow space 8 straight x equals 400
rightwards double arrow straight x equals 400 over 8
rightwards double arrow straight x equals 50
So comma space the space breadth space equals space straight x space equals space 50 space units space
and space the space length equals 3 straight x space equals space 3 left parenthesis 50 right parenthesis equals 150 space units end style

Answered by Rebecca Fernandes | 10th Mar, 2017, 08:46: AM