My son had his 18 months visit to the doctor last week. the nurse took several measurement while we were there. his length (height) is now 33 inches and his weight is 25.5 pounds. At birth he was 20 inches long and weighed 8 punds and 4 ounces. Determine what his weight and height would be if this growth pattern to continue.

18 months ...33inches, weight 25.5 pounds

When he was born = 9 months ...20 inches, weight 8, 4 pounds

Every 9 months his height growth is 33-20 = 13 inches, his weight is 25.5-8.4=17.1 pounds

Pounds. This means, for every 9 months, his growth is 13 inches and his weight is 17.1 pounds. For example we can determine his growth in 3 years.

3 years = 36 months, 36 = 9*4, his height will be 4*13 inches = 52 inches, his weight will be 4*17.1 = 68.4 pounds