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Geometry Vocabulary
Unit Review
Question | Answer |
---|---|
Ray | a part of a line that begins at a particular point (the endpoint) and extends forever in one direction |
Line | a two-dimensional object that has no endpoints and continues on forever in both directions |
line segment | part of a line connecting two points, it has definite end points |
Angle | the figure formed by two rays, called the sides of the angle, sharing a common endpoint (the vertex of the angle) |
vertex | the point at which the rays of an angle or the sides of a polygon meet; the plural form of the word is “vertexes” or “vertices” |
acute angle | an angle with a measure less than 90° |
obtuse angle | an angle with a measure more than 90° |
right angle | a 90° angle |
straight angle | a 180° angle |
reflex angle | an angle with a measure greater than 180° but less than 360° |
adjacent angle | two angles that are next to each other |
congruent sides | congruent sides or segments have the exact same length |
adjacent sides | two sides that share a common vertex |
parallel lines | lines that never meet; two parallel lines are always the same distance apart |
perpendicular | two lines that intersect at right angles |
regular polygon | a polygon in which all sides are the same length and all angles have the same measure |
polygon | a 2-dimensional figure formed by three or more line segments (sides) that meet only at their endpoints (vertices) to make a closed path; sides may not cross one another |
quadrangle | a polygon with four sides and four angles |
equilateral triangle | a triangle with all three sides equal in length, each angle of an equilateral triangle measures 60° |
isosceles triangle | a triangle with two sides equal in length |
scalene triangle | a triangle with no sides equal in length |
right triangle | a triangle with a right angle (90°) |
acute triangle | a triangle with three acute angles |
obtuse triangle | a triangle with one obtuse angle |
rhombus | a rhombus is a quadrilateral whose four sides are congruent; it has two pairs of parallel sides; squares are a type of rhombus with congruent angles |
square | a figure with four congruent sides and four right angles; a square is always a rhombus; all squares are considered rectangles |
rectangle | a figure with four sides and four right angles; opposite sides are parallel and congruent, a rectangle is sometimes a trapezoid; a rectangle is sometimes a square |
trapezoid | a quadrilateral with at least one pair of parallel sides |
parallelogram | a quadrilateral with two pairs of parallel sides; opposite sides have the same length and opposite angles have the same measure; all rectangles are parallelograms but not all parallelograms are rectangles because parallelograms do not necessarily ha |
concave polygon | a polygon with an angle measuring more than 180°; concave polygons look like they are collapsed or have one or more angles “dented” in |
convex polygon | a polygon is convex if there are no “dents” or indentations in it |