Flashcards: Mrs. Wilson's Geometry Terms
About these flashcards
Created by:
coryn_wilson on February 26, 2010
Subjects:
Description:
This is a list of geometry terms that all 8th graders should be familiar with.
Groups:
Awesome people!, Pcs 8th math, Geometry
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Terms | Definitions |
|---|---|
 line | a series of dots so close together that they appear as one continuous thing; there is no beginning or end to a "line". |
| ray | a part of a line that extends indefinitely from one direction |
| line segment | two endpoints and the straight path between them; a "line" with a beginning and an ending. |
| intersecting lines | two or more lines that meet and cross at any angle. |
| perpendicular lines | lines that intersect at a right angle |
| parallel lines | lines going in the same direction without touching; two lines (or line segments) with the same slope that are always the same distance apart. |
| congruent figures | figures that are the same size and shape |
| vertical | line going up and down |
| horizontal | lines going side to side |
| plane | is a flat two-dimensional surface that is unending in all directions |
| angle | two rays with a common endpoint |
| right angle | an angle that measures 90 degrees |
| acute angle | an angle with a measure greater than 0 degrees and less than 90 degrees |
| obtuse angle | an angle that measures greater than 90 degrees and less than 180 degrees |
| reflex angle | angle that measures more than 180 degrees and less than 360 degrees |
| complementary angle | if the sum of two angles measures 90 degrees |
| supplementary angle | if the sum of two angles measure 180 degrees |
| straight angle | 180 degree angle |
| transversal | a line that intersects two or more other lines at different points |
| pi | The value that shows the relationship of a circle's circumference to its diameter; it has an approximate value of 3.14 or the fraction 22/7 |
| polygon | a closed figure with three or more straight sides |
| circumference | the distance around the edge of a circle |
| two ways to measure triangles | side length and angle measures |
| right triangle | a triangle with one right angle |
| acute triangle | triangle whose interior angles are all acute |
| obtuse triangle | triangle that has one angle more than 90 degrees |
| equilateral triangle | a triangle with three congruent sides |
| isosceles triangle | a triangle with two equal sides, the two base angles are also equal |
| scalene triangle | all sides are different |
| measure of the interior angles of a triangle | 180 degrees |
| faces | the flat surfaces of a 3-D figure |
| edges | the intersection of faces of a 3-D figure |
| square | a parallelogram with all sides congruent and all angles congruent |
| rectangle | a quadrilateral with four right angles; opposite sides are parallel and congruent |
| trapezoid | a quadrilateral having two sides parallel |
| rhombus | a parallelogram with four equal sides |
| parallelogram | a quadrilateral that has both pairs of opposite sides parallel |
| circle | the set of all points in a plane that are the same distance from a given point |
| radius | the distance from the center of the circle to any given point on the circle |
| diameter | the distance across the circle through the center |
| circumference | the distance around a circle |
| arc | a curved line or segment of a circle |
| surface area | the sum of the areas of all the faces and bases of a solid figure; measured in square units |
| area | the number of the square units in a figure |
| perimeter | the distance around any closed figure |
| volume | the amount of space a 3-D figure containes; the number of cubic units in a 3-D figure. |
| quadrilateral | a polygon with four sides |
| pentagon | a polygon with five sides |
| hexagon | a polygon with six sides |
| heptagon | a polygon with seven sides |
| octagon | a polygon with eight sides |
| nonagon | a polygon with nine sides |
| decagon | a polygon with ten sides |
| solid | a three-dimensional (3-D) figure |
| base | the bottom side of a geometric figure from which the altitude or height can be constructed |
| dodecagon | a 12 sided polygon |
| prism | a 3-D figure that has two parallel and congruent bases in the shape of a polygon and at least three lateral faces shaped like rectangles; has a first name (after base) and last name is prism |
| pyramid | a solid figure that has a polygon for a base and triangles for sides; has a first name (after base) and last name is pyramid |
| cone | a 3-D figure with curved surfaces, a circular base, and one vertex |
| cylinder | a 3-D figure with ll curved surfaces, two circular bases, and no vertex; the net of a cylinder is formed by two circles and one rectangle |
| net | A two-dimensional pattern that can be folded to make a three-dimensional prism or pyramid |
| regular figure | a figure in which all sides are equal in length and all angles are of the same measure |
| equilateral | means that all sides are equal |
| sum | the answer to an addition problem |
| difference | the answer to a subtraction problem |
| product | the answer to a multiplication problem |
| quotient | the answer to a division problem |
| sum of the interior angles of a polygon | (n-2)180 ; with n as the number of sides in the figure |
| sum of the exterior angles of a polygon | ALWAYS 360 degrees |
| each interior angle of a regular polygon | 180 - (exterior angle measure) |
| each exterior angle of a regular polygon | 360 divided by (# of sides) |
| rhombus | has four equal sides |
| corresponding angles | angles that lie on the same side of a transversal and in corresponding positions |
| alternate interior angles | angles that lie within a pair of lines and on opposite sides of a transversal |
| adjacent angles | angles that share a vertex and a side but have no interior points in common |
| vertical angles | angles that are opposite from each other; formed from two intersecting lines |
| lateral area | the sum of the areas of the lateral surfaces (only the sides, no bases) of a 3-D figure |
| height of a figure | the perpendicular distance from the base to the opposite side of the figure (always forms a right angle with the base); also called the altitude |
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