| A | B |
|---|
| plane | a flat surface that extends indefinitely in all directions and has no thickness |
| intersecting lines | These lines lie in the same plan and have exactly one point in common |
| parallel lines | These lines lie in the same plan and never intersect |
| skew lines | Lines that lie in different planes. They aren't parallel nor intersecting. |
| point | A location - no size - named by a capital letter |
| line | a series of points that extend in opposite directions without end. |
| ray | A part of a line with one endpoint and all the points of the line on one side of the endpoint |
| segment | A part of a line with two endpoints and all points in between |
| acute angle | an angle with the measure between 0 - 90 degrees |
| right angle | an angle with the measure of 90 degrees |
| obtuse angle | an angle that measures between 90 - 180 degrees |
| straight angle | 180 degrees ( a straight line) |
| complementary angles | angles that together measure 90 degrees |
| supplementary angle | angles that together measure 180 degrees |
| adjacent angles | angles that share a vertex and a side but have no interior points in common |
| vertical angles | formed by 2 intersecting lines and are opposite each other |
| congruent angles | angles with equal measures |
| isosceles triangle | triangle that has at least 2 congruent sides |
| equilateral triangle | triangle that has 3 congruent sides |
| scalene triangle | triangle that has NO congruent sides |
| angle sum of a triangle | 180 degrees |
| circle | the set of points in a plane that are all the same distance from a given point, called the center |
| radius | a segment that connects the center of a circle to the circle |
| diameter | a segment that passes through the center of a circle and has both endpoints on the circle |
| central angle | an angle with its vertex at the center of a circle |
| chord | a segment that has both endpoints on the circle |
| arc | part of a circle |
| semicircle | half of a circle |
| transversal | a line that intersects two other lines at different points |
| rhombus | four congruent sides |
| quadrilateral | four sides |
| square | four right angles and four congruent sides |
| parallelogram | both pairs of opposite sides are parallel |
| trapezoid | exactly one pair of parallel sides |
| rectangle | four right angles |
| perpendicular lines | lines that intersect to form right angles |
| corresponding anles | angles that lie on the same side of the transversal and in corresponding positions |
| alternate interior angles | angles that are in the interior of a pair of lines and on opposite sides of the transversal |
| polygon | a closed plane figure with at least three sides, the sides meet only at their endpoints |
| congruent figure | figures that have the same size and shape, and their corresponding parts have equal measures |
| sigment bisector | a line, segment or ray that divides a segment into 2 congruent segments |
| perpendicular bisector | a line, segment or ray that is perpendicular to the segment that it bisects |
| angle bisector | a ray that divides an angle into 2 congruent angles |
| rotation | a transformation that turns a figure about a fixed point called the center of rotation |
| rotational symmetry | a figure has rotational symmetry if you can rotate it 180 degrees, or less so that tis image matches the orginal figure |
