Pediatrics General f969e95b At what age upper segment : Lower segment ratio becomes 1 : 1? A 3-6 years B 5-8 years C 7-10 years D 10-12 years High-Yield Explanation Age US : LS ratio Birth 3 years 7-10 years > 10 years 1.7 : 1 1.3 : 1 1 : 1 0.9 : 1