Question

find the least perfect square exactly divisible by 6 , 9 , 15 and 20​

Answer 1

Least no. which is exactly divisible

By 6,9,15,20 = lcm of 6,9,15,20

Prime factorisation of 6:2×3

Prime factorisation of 9:3×3

Prime factorisation of 15:3×5

Prime factorisation of 20:2×2×5

Do,lcm=highest power of factors

= 2×2×3×3×5=180

Now 180 = 2×2×3×3×5

To make it a perfect square we have to multiply it from 5 to make its paor complete

So,180×5=2×2×3×3×5×5

Hence 900 is the least perfect square which is divisible by all the given three no.

Hope it will help u