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
