Question

The length of a rectangular plot is 4m more than its breadth .if the area of the plot is 320sq.m ,find the length and breadth of the plot ?

Answer 1

S O L U T I O N :

Let the breadth of a rectangular plot be r metre & let the length of a rectangular plot be (r+4) metre .

We have area of the plot is 320 m² .

$\underline{\bf{Explanation\::}}$

As we know that area of the rectangle;

$\boxed{\bf{Area\:of\:rectangle = (length \times breadth)\:\:\:[sq.unit]}}$

A/q

$\mapsto\tt{[(r+4) \times r ] = 320 }$

$\mapsto\tt{r^{2} +4r = 320 }$

$\mapsto\tt{r^{2} +4r -320=0 }$

$\mapsto\tt{r^{2} + 20r - 16r -320 = 0\:\:\underbrace{\sf{Factorisation}}}$

$\mapsto\tt{r(r+20) -16(r+20) =0}$

$\mapsto\tt{(r+20) (r-16) =0}$

$\mapsto\tt{r+20 = 0\:\:\:Or\:\:\:r-16=0}$

$\mapsto\tt{r\neq -20\:\:\:Or\:\:\:r=16}$

As we know that negative value isn't acceptable .

r = 16 m

Thus;

• Length, (l) = (r + 4) = (16 + 4) = 20 m .
• Breadth, (b) = r = 16 m

The length & breadth of the plot will be 20 m & 16 m .

Answer 2

Answer:

The length & breadth of the plot will be 20 m & 16 m .

Step-by-step explanation: