Question

floor of a room of dimensions 5m×4m and it is covered with circular tiles of diameters 50cm each. find the area of the floor remains uncovered with tiles?

Answer 1

Diameter of one tile = 0.5 m
Number of tiles that can be laid along the length of the room = 5/0.5 = 10 tiles
Number of tiles that can be laid along the breadth of the room = 4/0.5 = 8 tiles 
Total tiles = 10 x 8 = 80 tiles
Area of 80 tiles = 80 x 3.14 x 0.25 x 0.25 m2  = 15.7 m2
Area of the floor  = 5 x 4 = 20 m2
Un-tiled area = 20 - 15.7 = 4.3 m2

Answer 2

Answer:

Step-by-step explanation:

As the diameter of circular tile is 50 cm each, then r =  = 0.25 m

Number of tiles length wise =  = 10 tiles

Number of tiles width wise =  = 8 tiles

So, 10 tiles are length wise and 8 tiles are width wise.

So, total number of tiles = 10 × 8 = 80.

∴ Area of floor not covered by tiles

= Area of rectangular floor – Area of 80 tiles

= 5 × 4 – 80πr2 = 20 – 80 × π × 0.25 × 0.25

= 20 –  = 20 –  = 20 – 15.7 = 4.3 m2

Hence, the area of floor not covered by tiles = 4.3 m2.