100 Word Vocabulary List Geometry（100字的词汇列表几何）.docVIP

100 Word Vocabulary List Geometry Geometry - branch of mathematics that deals with points, lines, planes and solids and examines their properties. Point – has no size; length, width, or height. It is represented by a dot and named by a capital letter. Line – set of points which has infinite length but no width or height. A line is named by a lower case letter or by any two points on the line. Plane – set of points that has infinite length and width but no height. We name a plane with a capital letter. Space – set of all points. Collinear points – points that lie on the same line. Noncollinear points – points that do not lie on the same line. Coplanar points – points that lie on the same plane. Noncoplanar points – points that do not lie on the same plane. Segment – part of a line that consists of two points called endpoints and all points between them. Ray- is the part of a line that contains an endpoint and all points extending in the other direction. Congruent segments – segments that have the same length. Bisector of a segment – line, ray segment, or plane that divides a segment into two congruent segments. Midpoint of a segment – a point that divides the segment into two congruent segments. Acute angle – angle whose measure is between 0 degrees and 90 degrees. Right angle – angle whose measure is 90 degrees. Obtuse angle – angle whose measure is greater than 90 degrees but less than 180 degrees. Straight angle – angle whose measure is 180 degrees. Congruent angles – angles that have the same measure. Angle bisector – ray that divides an angle into two congruent adjacent angles. Triangle – the figure formed by three segments joining three noncollinear points. Each of the three points is a vertex of the triangle and the segments are the sides. Acute triangle- triangle that has all acute angles. Right triangle – triangle with a right angle. Obtuse triangle – triangle with an obtuse angle. Equiangular triangle – triangle with all angles congruent. Scalene tri