the breadth of rectangle is 4 cm less than its length if the length is increased by 4 cm and the breadth is decreased by 1 cm the area of rectangle is increased by 40 cm square find the length and the breadth of the rectangle
Answers
let length of the rectangle be x
then , breath will be x-4 .
area = x ( x-4 )
= x^2 -4x
After decreasing
now length = x+4
breath = x-5
area = x+4 * x-5
= x^2 -5x +4x -20
= x^2 -x -20
A.T.Q
x^2 - 4x + 40 = x^2 -x -20
-4x +40 = -x -20
4x - x = 20 + 40
3x = 60
x = 20
thus , x-4 = 16
thus , the required value of length and breath are 20 , 16 respectively .
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Answer:
20 cm and 16 cm
Step-by-step explanation:
let the length of the rectangle be x cm
then breadth = (x - 4) cm
area of the rectangle = x(x - 4)
= (x² - 4x)cm²
as per the question,
=> (x+4)(x - 4 - 1) = (x² - 4x ) + 40 cm²
=> (x+4)(x - 5) = x² - 4x + 40
=> x² - x - 20 = x² - 4x + 40
=> 3x = 60 cm
=> x. = 20 cm
length = x = 20 cm
breadth = x - 4 = 16 cm