Baby Rats Data

In our science class there are rats and during the first quarter they had babies.  We started measuring and weighing them on the third day of their lives.  The first time we weighed our rat, it weighed 7.6 grams, it's tail was 20 millimeters, and the circumfrence of it's head was 50 millimeters.  We also measured them on the sixth, ninth, thirteenth, and forty-fifth day.  The ratio between the tail length and the circumfrence of the head was always changing and I kind of saw a pattern.  Evey time we measured the rats, the length of the tail got closer to the circumfrence of the head, which meant that the tail was growing faster than the head.  By day thirteen, the tail was 50 millimeters long and the head's circumfrence was 62 millimeters.  But after day thirteen we didn't measure them again until day 45.  By this time the tail had grown to 110 millimeters,  and the head was 75 millimeters.  So as you can see the tail was growing much faster than the head was.