Answer:
A. Answer is 2263.
Checkpoint 1 is -86 Checkpoint 4 is 2177
Subtract -86 from 2177....2177-(-86)
=2263
2263 is how much higher checkpoint 1 (-86) is from checkpoint 4 (2177)
B. 239 FEET.
the altitude of the hill must be subtracted by the depth of the ckeckpoint(2)(-189)
therefore the altitude of the hill comes out to be 428-189=239feet.
therefore,the actual altitude of the hill is 239 feet.
