Answer: The percentage of the offspring that will be homozygous dominant is zero.
Explanation: Since tall pea plants are dominant to short pea plants, a cross between a heterozygous tall pea plant (Tt) and a homozygous short pea plant (tt) will produce four offsprings: two heterozygous tall pea plants (Tt) and two homozygous short pea plants (tt). Tt x tt = Tt, Tt, tt, and tt.
Tt is heterozygous dominant for tall height while tt is homozygous recessive for short height.
See the attached punnet square for more information.