If both parents are 6 feet tall : It is possible to have a child that is 6'6" tall
If both parents are 6 feet tall and both parents have the tall dominant allele there is a possibility of having a child that is 6'6" tall. When both parents posses a h0m0zygous dominant genotype ( TT ) the probability of having a child which is taller than the parents is 100%.
Hence we can conclude that If both parents are 6 feet tall : It is possible to have a child that is 6'6" tall
Learn more about H0m0zygous dominant genotype : https://brainly.com/question/1626661