<prompt> Birth length is double at the age of1 years2 years3 years4 years  <response>: D. i.e. 4 years 4 Ghai 6th 6 - Ghai 7thWeightLength or heightHead circumferencebirth - about 3 kgbirth50 cmBirth34 cm5 monthDoubles6 kg1 years75 cm1 years45 cm1 years9 kg2years85 cm2years47 cm2 years12 kg3 years95 cm 3 years14 kg4 yearsdoubles100 cm3 years49 cm4 years16 kg 4 years50 cm A useful guide for normal range is target height 7 cm for girls and target height 8.5 cm for boys 