Answer:
36
Step-by-step explanation:
Multiples of 4 (from 1-40)
4, 8, 12, 16, 20, 24, 28, 32, 36, 40
Multiples of 8 (from 1-40)
8, 16, 24, 32, 40
4, 12, 20, 28, 36 is one of them. Find out the factors of the 5 numbers.
4 = 1 x 4
12 = 1 x 12
= 2 x 6
= 3 x 4
20 = 1 x 20
= 2 x 10
= 4 x 5
28 = 1 x 28
= 2 x 14
= 4 x 7
36 = 1 x 36
= 2 x 18
= 3 x 13
= 4 x 9
= 6 x 6
That's about it, so 12 or 36 is the answer. Now find out which of the 2 numbers is a perfect square.
To find out a perfect square, the 2 numbers multiplying in have to be the same number.
6 x 6 = 36
So 36 is a perfect square since there are no 2 numbers which are the same value that can make up 12.
