A rectangular courtyard is 18 m 72 cm long and 13 m 20 cm broad. It is to be paved with square tiles of the same size. Find the least possible number of such tiles.
Length of the courtyard = 1872 cm
Breadth of the courtyard = 1320 cm
To find the size of the tile we need to calculate HCF of length and breadth
Using Euler’s division lemma: a = pq + r where 0≤r<p
1872 = 1320 × 1 + 552
1320 = 552 × 2 + 216
552 = 216 × 2 + 120
216 = 120×1 + 96
120 = 96 ×1 + 24
96 = 24 × 4 + 0
Therefore HCF of 1872 and 1320 is 24
Number of tile = 
= 
= 4290 tiles
14