Slope of line t is -1/5
If two lines are perpendicular, the product of their slopes is -1
25 = 5^2
90 = 2 . 3 . 3 . 5
GCF is not as greedy as LCM.
GCF is just on a diet, so it takes the same number and the smallest amount.
25 and 90 both have 5.
5^2 or 5 ?
Take the smaller one.
GCF = 5
