Given numbers = 6, 9, 15 and 20
The smallest number divisible by 6, 9, 15 and 20 is their L.C.M. i.e. 180
Resolving the L.C.M. as prime factors we get, 180= 2 × 2 × 3 × 3 × 5
To make it perfect square multiply by 5 then it becomes, 180= 2 × 2 × 3 × 3 × 5 × 5
Which implies 180 × 5 = 900
Least square number which is exactly divisible by 6, 9, 15 and 20 is 900.
