What is the smallest perfect square which is completely divisible by each of 16, 18 and 36?

144 81 196 169

144

16 = 2 × 2 × 2 × 2 20 = 2 × 2 × 5 24 = 2 × 2 × 2 × 3 LCM of 16, 20 and 24 = 2 × 2 × 2 × 2 × 3 × 5 = 240 To make number perfect square multiply by 3 and 5 in 240 ⇒ 240 × 3 × 5  ⇒ 3600