A room that is 40 feet by 65 feet with a 10-foot-high joisted ceiling will be protected with heat detection. The joists are 12 inches deep and run in the 40-foot direction. The engineer specified heat detectors with a 50-foot listed spacing. How many heat detectors are required for this room?

in cartography, a contour line (often just called a "contour") joins points of equal elevation (height) above a given level, such as mean sea level. a contour map is a map illustrated with contour lines, for example a topographic map, which thus shows valleys and hills, and the steepness or gentleness of slopes.

explanation:

the answer is c.the valence of the atoms combine .