Question

what is length and breadth of a rectangle if perimeter and area is 21m and 26sq.m respectively?

Answer 1

Heya!!!

Let the length of rectangle be L and its breadth be b

It's area = L × b

and it's perimeter = 2 ( L + b )

According to the question

L × b = 26 ... equation 1

2 ( L + b ) = 21 .... equation 2


2 ( L + 26 / L ) = 21


2L² + 52 = 21 × L


2L² -21L + 52 = 0


L = 21 + √{ ( 21 )² - 4 ( 2 ) ( 52 ) } / 2 ( 2 )

By using quadratic formula.

L = 21 + √ ( 25 ) / 4

L = 21 + 5 / 4


L = 26 / 4

L = 6.5m

or

L = 21 - √ { ( 21 )² - 4 ( 2 ) ( 52 ) } / 2 ( 2 )


L = 21 -5 / 4

L = 4


For L = 6.5m b = 4m

For L = 4 b = 6.5m



Have a nice time!!!!