Find the leash number of square tiles required to pave the ceiling of a room 15 m 17

It is given that:

Length of a tile = 15 m 17 cm = 1517 cm                  [∵ 1 m = 100 cm]
Breadth of a tile = 9 m 2 cm = 902 cm
∴ Side of each square tile = HCF (1517, 902)
Prime factorisation:

$1517=37 \times 41$

$902=22 \times 41$

∴ HCF = Product of smallest power of each common prime factor in the numbers = 41          

$\therefore$ Required number of tiles $=\frac{\text { Area of ceiling }}{\text { Area of one tile }}=\frac{1517 \times 902}{41 \times 41}=37 \times 22=814$