Bobby wants to cover a floor measuring 140 cm by 80 cm with square tiles of the same size. Given that he uses only whole tiles, find
- the largest possible length of the side of each tile.
- the number of tiles that are needed to cover the floor.
(a)
Factors of 80: 1, 2, 4, 5, 8, 10, 16, 20, 40, 80
Factors of 140: 1, 2, 4, 5, 7, 10, 14, 20, 28, 35, 70, 140
The highest common factor of 80 and 140 is 20.
Largest possible length of the side of each tile = 20 cm
(b)
Number of tiles arranged lengthwise
= 140 ÷ 20
= 7
Number of tiles arranged breadthwise
= 80 ÷ 20
= 4
Number of tiles to cover the floor
= 7 x 4
= 28
Answer(s): (a) 20 cm; (b) 28