Aveterinarian needs to know animals weight in kilograms. if 20 pounds is about 9 kilograms and a dog weights 30 pounds, use a ratio table to find the dogs weight explain

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).