my 4 month 10days old boy having a weight of 5.4 kg and height of 64cm. is that normal

A. Yes it is but just for your information birth weight does play a very important role in this you have to check how much I have your child gains in these 4 1/2 month it will practically be somewhere around 4 to 500 g more than the birth weight every month your child should be so by now your child should have gained about 2 to 2 1/2 KG