What do coordinate systems use to represent a location on the earth's surface?

The correct answer is that coordinate systems use coordinates to represent a location on the earth's surface. Coordinates are numerical values that define a specific point in space, typically expressed in terms of latitude and longitude for geographic coordinate systems or as x and y values for projected coordinate systems.

Coordinates provide a systematic way to pinpoint exact locations on a map and allow for accurate navigation and spatial analysis. For example, geographic coordinates represent a point's position in relation to the equator (latitude) and the prime meridian (longitude), while projected coordinates might place a point in a two-dimensional space based on a specific projection.

While angles, distances, and numbers play roles in various calculations and representations in geographic information systems, they are not the primary means by which locations are defined within coordinate systems. Rather, coordinates specifically serve this function, making them an essential concept in geospatial analysis and mapping.