Step-by-step explanation:

Question - The length of a rectangle is four times its breadth. If the perimeter is 30 cm, find the area.

Solution - Perimeter of Rectangle= 30 cm

Let Breadth be x cm,

According to question,

Let Length be 4x cm.

Perimeter of Rectangle = 2(L+B) unit

30cm = 2(x+4x)cm

30cm = 2 × 5x cm

30cm = 10x cm

x cm = 30/10 cm

x = 3

We will not write the unite because x is a variable..

Breadth = X cm = 3 cm

Length = 4x cm = 4×3 cm = 12 cm

Area of Rectangle= L×B unit²

= 12×3 cm²

= 36 cm²

So, Option (3) 36 cm ² is correct.

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