For that problem: A board that is 12 feet long must be cut into 2 pieces that have lengths in a ratio of 3 to 2. Find the lengths of the two pieces.

Question

when answering the question why was it 3/5=x/12? where did the 5 come from?

Answer 1

With a ratio of 3:2, your total is 5. You're figuring 3 parts of 5.

Answer 2

but arn't you figuring 2 parts because its cut in two??

Answer 3

Please read my explanation.

http://www.jiskha.com/display.cgi?id=1298850580