Answer:
Harris is right
Explanation:
That actually works with all numbers.
What Harris did to 15 x 9 is multiply the 15 by 3 to get 45 and divide 9 by 3 to get 3.
So since he multiplied one of the "dimensions" by 3 and divided the other by 3 the product of the 2 dimensions is the same as the original.
Goos Luck!