Question

the area of rectangle is 21 cm square. if one side exceeds the other by 4 cm .find the dimension of the rectangle

Answer 1

Answer:

length of rectangle = 7 cm

breadth of rectangle = 3 cm

Explanation:

let the length of rectangle = x

and breadth of rectangle = y

A.T.Q

xy = 21 -------(1)

x - y = 4 ------(2)

x = y + 4

put x in eq 1

(y + 4)y = 21

y² + 4y - 21 = 0

y² + 7y - 3y - 21 = 0

y(y + 7).-3(y + 7) = 0

(y + 7)(y - 3) = 0

y + 7 = 0 , y - 3 = 0

y = -7 , y = 3

sides are not negative so y = 3

put y in eq 2

x - y = 4

x - y = 4

x - 3 = 4

x = 4 + 3

x = 7

Answer 2

Explanation:

Here the right answer is the length will be 7 cm and the breadth will be 3 cm which implies 7 x 3 equals to 21 cm^2. So, the dimension of the area of the rectangle will be 21 cm^2. You can go through the steps for the same in your lesson and revise the formula to come to the right conclusion.