5th box -Flashcards

It is even and its digits add to a multiple of 3.

1

The resulting equation is inversely proportional (not proportional, like a baking recipe). So, set up a proportional equation and then flip one of the sides. It is important to use the same units on each side! 15/9 = 21/x -> 15/9 = x/21 -> x=35.

(x/360*pi*r^2