is the slope of the line. So, the slope of the line is calculated by rise/run. The rise is how up or down it goes from a certain point to another, and the run is how right or left it goes from a certain point to the other.
The ratio is 3:2, purple :green The bag has 21 purple so to get from 3 to 21 it is multiplied by 7; so we must also multiply the 2 by 7 to keep the ratio balanced. 21:14