In geometry, formal meanings are developed using other defined words or terms. Over there are, however, 3 words in geometry that are not formally defined. This words are point, line and plane, and are referred to as the "three undefined regards to geometry".
You are watching: The three undefined terms in geometry
While this words space "undefined" in the official sense, we can still "describe" these words. The descriptions, declared below, describe these native in relationship to geometry.
POINT • a allude indicates a place (or position) in space. • a allude has no dimension (actual size). • a point has no length, no width, and no elevation (thickness). • a suggest is usually called with a capital letter. • in the name: coordinates plane, a point is named by an ordered pair, (x,y). if we represent a suggest with a dot, the dot can be really tiny or an extremely large. Remember, a point has no size.
The size of the dot attracted to stand for a suggest makes no difference. Points have no size. They merely represent a location.
LINE (straight line) • a line has no thickness. • a line"s length extends in one dimension. • a heat goes on forever in both directions. • a line has infinite length, zero width, and also zero height. • a line is presume to be straight. • a line is attracted with arrow head on both ends. • a heat is named by a solitary lowercase manuscript letter, or by any kind of two (or more) points i m sorry lie on the line.
Lines can be labeled v a single script letter, or by 2 points on the line,
. The thickness the a line renders no difference.
See more: Calories In 1 Oz Dry Oatmeal Equals How Much Cooked ? How Many Cups Of Oatmeal In 1 Ounce
PLANE • a plane has two dimensions. • a aircraft forms a flat surface extending indefinitely in every directions. • a airplane has infinite length, infinite width and zero elevation (thickness). • a aircraft is drawn as a four-sided number resembling a tabletop or a parallelogram. • a airplane is named by a single letter (plane m) or by three coplanar, yet non-collinear,* clues (plane ABC).
aircraft m or airplane ABC. If the chart of a airplane has edges, you need to remember that the aircraft actually has no boundaries.
* upright points are points the lie ~ above the same straight line. Coplanar points are points the line in the same plane.