Complete the magic hexagon by filling in the missing numbers.

The number on the sides of magic hexagon will be the product of the numbers at it's respective corners.

So, the missing numbers starting from left will be:
5 x 4 = 20,
4 x 6 = 24,
6 x 2 = 12

Now, the product of the missing number at the corner and 2 should be 18. Thus, the missing number is 9, as 2 x 9 = 18

Then, 9 x 8 = 72,
and 8 x 5 = 40

Thus, upon filling the missing numbers, the magic hexagon will look like as shown below.