Answer:
B) 6.5 inches by 3.5 inches
Explanation:
Multiplying the actual dimensions by the scale gives the scale dimensions:
(0.5 in)/(6 ft) × {78 ft, 42 ft}
= {39/6 in, 21/6 in}
= {6.5 in, 3.5 in}
The size on the scale drawing is 6.5 inches by 3.5 inches.