To find the smallest number that 72 can be multiplied by to make a perfect square, we can break down 72 into its prime factors.
The prime factorization of 72 is:
72 = 2^3 * 3^2
To make it a perfect square, we need to make sure that each prime factor has an even exponent. Since 2 has an odd exponent (3), we need to multiply 72 by another 2 to make it a perfect square.
So, the smallest number that 72 can be multiplied by to make a perfect square is 2.
Therefore, 72 * 2 = 144, which is a perfect square (12^2).