The area of a square of 12 cm side equals that of the area of a rectangle of 16 cm in length. What is the perimeter of the rectangle?

The side of the square = 12 cm

∴ The area of the square = side x side

 = 12 cm × 12 cm = 144 cm²

The length of the rectangle = 16 cm.

Let the breadth of the rectangle be b.

∴ The area of the rectangle = 16 cm × b

It is given that,

Area of the square = Area of the rectangle

∴ 144 cm² = 16 cm × b

$\Rightarrow \mathrm{b}=\frac{144}{16}=9 \mathrm{cm}$

The perimeter of the rectangle = 2 x (length + breadth)

= 2 × (16 cm + 9 cm) 

= 2 × 25 cm = 50 cm.

Therefore, the perimeter of the rectangle is 50 cm.