A tile is a square of side 20 cm. How many would such tiles be required to cover the floor of a square bathroom of side 3 m?

Given:

Side of square tile = 20 cm

Side of square floor = 3 m

We have 1 m = 100 cm

⇒ Side of floor = 3 × 100 cm = 300 cm

We know, area of a square = side²

⇒ Area of square tile = (20)²

∴ Area of square tile = 400 cm²

Similarly, Area of square floor = side²

⇒ Area of square floor = (300)²

∴ Area of square floor = 90000 cm²

Let the number of tiles required be x.

1 tile covers an area of 400 cm².

x tiles cover an area of 90000 cm².

∴ x = 225

Thus, 225 tiles are required to cover the floor.