Select one:
a. 352 ft
b. 275 ft
c. 280 ft
d. 285 ft
also explain how you got your answer

You know from the definitions of trig functions that
.. tan(42°) = (height of courthouse above measuring device)/(distance to courthouse)
.. (height of courthouse above measuring device) = tan(42°)*(305 ft) ≈ 274.6 ft

Since the measuring device is 5 ft high, the height of the courthouse is approximately 280 ft. (selection C)