Theory question 103
Mensuration of Plane ShapesA circular floor of a building is to be tiled with ceramic tiles each of side 40 cm × 40 cm. If the perimeter of the floor is 66 m. Calculate, correct to the nearest whole number, the number of tiles required to completely tile the floor. [Take π = 22/7]
Show the model answer
Model answer
2πr = 66 ⇒ r = 66 × 7 ÷ 44 = 10.5 m
Area of floor = 22/7 × 10.5² = 346.5 m²
Area of one tile = 0.4 × 0.4 = 0.16 m²
Number of tiles = 346.5 ÷ 0.16 ≈ 2165.6 ≈ 2166 tiles
Explanation
Work in metres throughout: 40 cm = 0.4 m.