The average adult male femur is 48 centimeters (18.9 in) in length. So a femur 10 inches longer is now 28.9 inches.
Robert Wadlow’s femur was 28.5″
If we multiply the length to a solid regression formula that shows itself accurate with giant application which is 3.7575 You get:
9.0493125 feet tall which is about 9’5″ Nearly accurate to 5″ taller than Robert Wadlow.
So, we are talking about someone 9.5″ in death and 9’8″ when alive.
Collins Historical Sketches of Kentucky V. II, History of Kentucky, 1874. page 35.