See attached picture for solution:
this would be 94 hope it helps
That is quite simply and astoundingly:
3.482 x 10^9
Part A :
D = (1/4) * C D = 1/4 * 24 D = 24/4 = 6 ft above sea level
Part B :
Your answer is positive because D is still above sea level...if it would have been below sea level, then it would have been negative