The perimeter of a rectangle is 30.8 km and it’s diagonal length is 11 km. find it’s length and width

Length of the rectangle is 15.0325 km and width is 0.3765 km.

Explanation:

Given:

Perimeter of a rectangle = 30.8 km

Length of diagonal of rectangle = 11 km

To find:

The length and width of rectangle=?

Solution:

Lets assume length of the rectangle = x km

And assume width of the rectangle = y km

Lets first create equation using given  perimeter

perimeter of rectangle = 2 ( length +  width )

=> 30.8 km = 2 ( x + y )  

=>

=> y = 15.4 – x             ------(1)

As diagonal and two sides of rectangle forms right angle triangle whose hypoteneus is diagonal ,  

=>

=>

=>

On substituting value of y from (1) in above equation we get

=>

=>

=>

=>

Solving above quadratic equation using quadratic formula

General form of quadratic equation is  

And quadratic formula for getting roots of quadratic equation is  

As equation is , in our case

a = 2 ,  b = -30.8 and c = 116.16

Calculating roots of the equation we get

=> x = 15.0325 or x = 0.3675

As generally length is longer one ,  

So x = 1.0325

From equation (1) y = 15.4 – x = 0.3765

Hence length of the rectangle is 15.0325 km and width is 0.3765 km.

step-by-step explanation: