Geometry, jee AHM uh tree, is a branch of mathematics that involves studying the shape, size, and position of lines, angles, curves, and figures. The figures studied in geometry include plane (flat) figures, such as circles, triangles, and rectangles; and solid (three-dimensional) figures, such as cubes, cones, and spheres. The name geometry comes from two Greek words meaning earth and to measure. The earliest uses of geometry included measuring lengths and areas of land. Most scholars believe that the ancient Egyptians and Babylonians were the first people to use geometry extensively.
Geometric shapes fill the world around us. For example, honey bees build their honeycombs in a pattern of hexagons, and earthworms are shaped like cylinders. Most houses and buildings have walls shaped like rectangles, and many bridges have supports shaped like triangles. By knowing something about geometry, we can better understand and appreciate our world.
Geometry has many practical uses. To construct stable and attractive buildings, architects and carpenters, for example, must understand the characteristics of geometric objects. Navigators of airplanes, ships, and spacecraft rely on geometric ideas to chart and follow a set course. Artists, designers, engineers, and photographers also use geometric principles in their work.
