Geometry - High School

If you feel obtuse when it comes to angles, review this list of geometry terms. You'll learn about planes, polygons, perimeter, and more. It's as easy as pi!
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Full list of words from this list:

words only definitions & notes
  1. acute
    (of an angle) less than 90 degrees
  2. acute angle
    an angle less than 90 degrees but more than 0 degrees
  3. altitude
    the perpendicular distance from the base of a figure
  4. angle
    the space between two lines or planes that intersect
  5. arc
    a continuous portion of a circle
  6. area
    the extent of a two-dimensional surface within a boundary
  7. bisect
    cut in half or cut in two
  8. center
    a point equidistant from the ends of a line
  9. chord
    a straight line connecting two points on a curve
  10. circle
    a plane curve with every point equidistant from the center
  11. circumference
    the length of the closed curve of a circle
  12. circumscribe
    draw a geometric figure around another figure
  13. collinear
    lying on the same line
  14. compass
    drafting instrument used for drawing circles
  15. cone
    a shape with a circular base and sides tapering to a point
  16. congruent
    coinciding when superimposed
  17. conic section
    (geometry) a curve generated by the intersection of a plane and a circular cone
  18. constant of proportionality
    the constant value of the ratio of two proportional quantities x and y; usually written y = kx, where k is the factor of proportionality
  19. coordinate
    a number that identifies a position relative to an axis
  20. coordinate system
    a system that uses coordinates to establish position
  21. coplanar
    lying in the same plane
  22. cosine
    ratio of the adjacent side to the hypotenuse of a right-angled triangle
  23. cross-section
    representing a plane made by cutting across something at right angles to its length
  24. cylinder
    a solid bounded by a round surface and two parallel planes
  25. degree
    a measure for arcs and angles
  26. derive
    reason by deduction; establish by deduction
  27. diagonal
    a straight line connecting nonadjacent vertices of a polygon
  28. diameter
    the length of a straight line through the center of a circle
  29. dissection
    the act of cutting so as to separate into pieces
  30. ellipse
    a closed plane curve with an oval shape
  31. endpoint
    a place where something ends or is complete
  32. equidistant
    exactly as far from one point as from another
  33. equilateral triangle
    a three-sided regular polygon
  34. Euclidean geometry
    (mathematics) geometry based on Euclid's axioms
  35. exterior angle
    the supplement of an interior angle of a polygon
  36. focus
    the concentration of attention or energy on something
  37. formula
    a group of symbols that make a mathematical statement
  38. function
    what something is used for
  39. geometric mean
    the mean of n numbers expressed as the n-th root of their product
  40. hexagon
    a six-sided polygon
  41. hyperbola
    an open, symmetrical plane curve with two branches
  42. hypotenuse
    the side of a right triangle opposite the right angle
  43. hypothesis
    a tentative insight that is not yet verified or tested
  44. input
    signal going into an electronic system
  45. inscribe
    carve, cut, or etch into a material or surface
  46. interior angle
    the angle inside two adjacent sides of a polygon
  47. isosceles
    (of a triangle) having two sides of equal length
  48. isosceles triangle
    a triangle with two equal sides
  49. line
    a length between two points
  50. midpoint
    a point equidistant from the ends of a line or the extremities of a figure
  51. model
    a hypothetical description of a complex entity or process
  52. obtuse
    of an angle, between 90 and 180 degrees
  53. obtuse angle
    an angle between 90 and 180 degrees
  54. output
    final product; the things produced
  55. parabola
    a symmetrical, approximately U-shaped curve
  56. parallel
    being everywhere equidistant and not intersecting
  57. parallelogram
    a quadrilateral whose opposite sides are parallel and equal
  58. partition
    divide into parts, pieces, or sections
  59. perimeter
    a line enclosing a plane area
  60. perpendicular
    intersecting at or forming right angles
  61. pi
    the ratio of the circumference to the diameter of a circle
  62. plane
    an unbounded two-dimensional shape
  63. point
    a geometric element that has position but no extension
  64. polygon
    a closed plane figure bounded by straight sides
  65. postulate
    a proposition accepted as true to provide a logical basis
  66. prism
    a polyhedron with two congruent and parallel faces
  67. proof
    a formal series of statements showing that something is true
  68. proportionality
    harmonious arrangement or relation of parts or elements within a whole (as in a design)
  69. pyramid
    a polyhedron having a polygonal base and triangular sides
  70. radian
    the unit of plane angle adopted under the Systeme International d'Unites; equal to the angle at the center of a circle subtended by an arc equal in length to the radius (approximately 57.295 degrees)
  71. radius
    the length of a line between a circle's center and perimeter
  72. ratio
    relation with respect to comparative quantity or magnitude
  73. ray
    (mathematics) a straight line extending from a point
  74. rectangle
    a parallelogram with four right angles
  75. reflection
    transformation in which the direction of an axis is reversed
  76. regular polygon
    a polygon with all sides and all angles equal
  77. right angle
    the 90 degree angle between two perpendicular lines
  78. right triangle
    a triangle with one right angle
  79. rotation
    a transformation in which the coordinate axes are turned
  80. scale factor
    a number used as a multiplier in scaling
  81. scalene
    having three sides of different lengths
  82. sector
    a plane figure bounded by two radii and the arc of a circle
  83. similarity
    the quality of being alike
  84. sine
    ratio of the length of the side opposite the given angle to the length of the hypotenuse of a right-angled triangle
  85. slope
    the property of a line that departs from the horizontal
  86. sphere
    a solid figure bounded by a round surface
  87. square
    a polygon with four equal sides and four right angles
  88. superposition
    (geometry) the placement of one object ideally in the position of another one in order to show that the two coincide
  89. symmetry
    exact reflection of form on opposite sides of a line
  90. tangent
    ratio of the opposite and adjacent sides of a right triangle
  91. theorem
    a proposition deducible from basic postulates
  92. three-dimensional
    involving or relating to three dimensions or aspects
  93. transformation
    a change in the position of a figure on a coordinate plane
  94. translation
    when the coordinate system origin moves to another position
  95. transversal
    extending or lying across
  96. trapezoid
    a quadrilateral with one pair of parallel sides
  97. triangle
    a three-sided polygon
  98. trigonometric function
    function of an angle expressed as a ratio of the length of the sides of right-angled triangle containing the angle
  99. trigonometry
    the mathematics of three-sided figures and their functions
  100. two-dimensional
    involving measurements of magnitude in two directions
  101. vertex
    the point of intersection of lines
  102. volume
    the amount of 3-dimensional space occupied by an object
  103. x-axis
    the horizontal axis in a plane coordinate system
  104. y-axis
    the vertical axis in a plane coordinate system
Created on Thu Feb 09 12:47:20 EST 2017 (updated Wed Mar 29 15:53:42 EDT 2017)

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