sea level

A roller coaster begins at 90 feet above ground level. Then it descends 105 feet. Find the height of the roller coaster after the first descent. 90 feet above ground level is written as +90 Descending 105 feet means we subtract 105 feet to get: +90 - 105 = -15 or 15 feet below ground level

Mount McKinley in Alaska, the highest mountain in North America, is 20,320 feet above sea level. Death Valley, the lowest point, is 280 feet below sea level. What is the difference in height between Mount McKinley and Death Valley? Regarding height with respect to sea level... Above sea level...