Term | Definition | Example |
POINT | A location in space. | (picture needed) |
LINE | A series of points that continues in two directions and never ends. | (picture needed) |
RAY | A part of a line that has one endpoint and continues in one direction without ending. | (picture needed) |
LINE SEGMENT | A part of a line that has two definite endpoints. | (picture needed) |
PLANE | A flat surface that continues in all directions without end. | (picture needed) or real-life examples: sheet of paper, floor, ceiling, wall, etc. |
COLLINEAR | The condition where two or more points lie in a line. | (picture needed) |
PARALLEL | The condition where two or more figures lie alongside each other and never intersect. | (picture needed) |
ANGLE | A figure formed by two rays or line segments that begin at the same point. | (picture needed) |
VERTEX | The common endpoint of two or more rays or line segments. | (picture needed) |
ACUTE ANGLE | An angle whose measure is between 0 and 90 degrees. | (picture needed) or list an angle and its measure: angle ABC is 30 degrees, therefore it is an acute angle |
RIGHT ANGLE | An angle whose measure is exactly 90 degrees. | (picture needed) or list an angle and its measure: angle ABC is 90 degrees, therefore it is a right angle |
OBTUSE ANGLE | An angle whose measure is between 90 and 180 degrees. | (picture needed) or list an angle and its measure: angle ABC is 137 degrees, therefore it is a obtuse angle |
STRAIGHT ANGLE | An angle whose measure is exactly 180 degrees. | (picture needed) or list an angle and its measure: angle ABC is 180 degrees, therefore it is a straight angle |
PERPENDICULAR | The condition where two figures intersect at a right angle. | (picture needed) or list an example: line AB is perpendicular to line CD, because they intersect at a right angle |
CONGRUENT | Having the same length or measure. | (picture needed) or list an example: segments AB and CD are congruent, because AB = 5 inches and CD = 5 inches |