Question

The area of a rectangle is 21 cm². If one side exceeds the other by 4 cm, find the

dimensions of the rectangle.
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Answer 1

Explanation:

GIVEN:-

Area = 21cm^2

Let Breadth = x cm

UNDERSTANDING THE CONCEPT:-

According to your question,

If breadth = x cm , length will be ( x + 4 )cm.

FORMULA:-

Area = length × Breadth

SUBSTITUTION:-

`21 = (x)(x + 4)`

`0 = x {}^(2) - 4x - 21 \\`

`0 = x {}^(2) + 7x - 3x - 21 \\`

`0 = x(x + 7) - 3(x + 7) \\`

`0 = (x - 3)(x + 7) \\`

`x = 3`

(- 7 will be neglected)

Breadth = 3 cm

Length = x + 4

= 7 cm

SO, The dimensions of rectangle is 7cm,3cm

Answer 2

7*3

Explanation:

a*b= area of rectangle

a+4=b

a(a+4)=21

a^2+4a-21=0

a=3 or a=-7

a length can't be negative so a=3

b is a+4 =3+4=7