Answer:
C) 7 ft 4 in
Step-by-step explanation:
Shadows are assumed to be proportional to the height of the object casting them. Hence the brother's shadow will satisfy ...
shadow/(6 ft) = (5.5 ft)/(4.5 ft) = 11/9 . . . . . reduce the fraction
shadow = (6 ft) · (11/9) . . . . . . . . . . . . . . . . . multiply by 6 ft
shadow = 7 1/3 ft = 7 ft 4 in