A square has a perimeter of 36 cm. Find the length of one side and its area.

Given, perimeter of square = 36 cm.

By formula, Perimeter of a square = 4 × side.

$\Rightarrow 4 \times \text{side} = 36 \\[1em] \Rightarrow \text{side} = \dfrac{36}{4} \\[1em] \Rightarrow \text{side} = 9 \text{ cm}.$

By formula, Area of a square = side × side.

$\Rightarrow$ Area = 9 × 9 = 81 cm²

Hence, the length of one side = 9 cm and area = 81 cm².