Pounds: 10 20 30
Kilos: 4.5 9 13.5
half of 20 is 10, and half of 9 is 4.5. So every 10 pounds is 4.5 kilos. Add 10 to 20 to get 30, and add 4.5 to 9 to get 13.5. Both parts of the ratio table are increasing at the same rate (either 10 eachtime or 4.5 each time).
