Area of a square is equal to ten times the area of a rectangle of edge 5 cm × 8 cm. What is the perimeter of the square?

Correct option is B

Given:

Rectangle dimensions: 5 cm × 8 cm

Area of square = 10 × Area of rectangle

Formula Used:

Area of a rectangle = length × breadth

Area of square = side²

Perimeter of square = 4 × side

Solution:

​$$\text{Area}_{\text{rectangle}} = 5 \times 8 = 40 \, \text{cm}^2$$​​

​$$\text{Area}_{\text{square}} = 10 \times 40 = 400 \, \text{cm}^2$$​​

Side of square $$= \sqrt{400} = 20 \, \text{cm}$$​​

Perimeter = $$4 \times \text{side}$$​​

Perimeter = 4 × 20 = 80 cm