Hi Rajib,

There are many rectangles with a perimeter of 24 units and each with a different area. For example a rectangle which is 11 units by 1 unit has a perimeter of 24 units and an area of $11 \times 1 = 11$ square units. Another rectangle which is 7 units by 5 units has a perimeter of 24 units and an area of $7 \times 5 = 35$ square units. The dimensions do not have to be integers. A rectangle which is $4 \frac12$ units by $7 \frac{1}{2}$ units has a perimeter of 24 units and an area of

$$4 \frac12 \times 7 \frac12 = \frac92 \times \frac{15}{2} = \frac{9 \times 15}{2 \times 2} = \frac{135}{4} = 33 \frac34 \mbox{ square units.}$$

Penny