If she is 51 inches, and you want to find the height in feet and inches, just add 12 each times from zero, and since 12 inches is equal to one foot, we can determine the following: 12 can go into 51 about 4 times, which is roughly 48 inches. Then, just subtract 48 from 51, and the answer to that is 3. And since we already know that 48 inches is 4 feet, then all you need to do is add the 3 inches that are left, and you get 4' 3'', or four feet and three inches. I hope this helps you, have a great day!