Geometry Definitions

  1. How do you name a line?
    single lower case letter OR two points contained on the line
  2. How do you name a plane?
    capital letter OR 3 noncollinear points
  3. How do you name a segment?
    the two endpoints
  4. How do define a point, line and plane?
    They are UNDEFINED.
  5. Collinear Points
    all points lie on the same line
  6. Coplanar
    all points lie on the same plane
  7. Where does a point and a line intersect?
    intersect at a point
  8. Where do 2 lines intersect?
    one point
  9. Where does a line and a plane intersect?
    it depends.

    • poked through = one point
    • whole line = infinite amount of points
  10. Where do two planes intersect?
    At a line
  11. What is a space?
    the set of all points
  12. AB
    a length
  13. AB^___ (with line over top)
    a segment
  14. Congruent
    same size and shape
  15. Tick Marks
    indicate congruency (shape but not size)
  16. Midpoint
    the midpoint of segment AB is the point between A & B where AM=MB
  17. segment bisector
    segment, line, or plane that intersects a segment at its midpoint
  18. ray
    one a line, 1 point (endpoint) and all points extending off in one direction
  19. angle
    figure formed by 2 non-collinear rays having same endpoint
  20. congruent angles
    <'s with the same measure
  21. Angle bisector
    divides an angle into 2 CONGRUENT angles
  22. adjacent angles
    have a common side and vertex, No overlap or gap.
  23. vertical angles
    2 non-adjacent angles formed by intersecting lines
  24. linear pair
    • adjacent angles whose non-common sides form opposite rays.
    • (sum of measures= 180)
  25. complementary angles
    2 angles whose sum is 90
  26. supplementary angles
    2 angles whose sum is 180
  27. perpendicular lines (upside down T)
    • intersect to form right angles
    • form adjacent angles
    • (rays,segments or planes can be perpendicular)
  28. inductive reasoning
    using examples to make a conjecture
  29. counterexample
    example proving a conjecture false
  30. statement
    sentence which is either T or F (truth value)
  31. negation
    opposite of a statement (not...) (~p)
  32. compound statement
    join 2 statements
  33. conjunction
    joined with the word AND

    T=both true
  34. disjunction
    joined with OR

    T=at least one true
  35. venn diagrams
    conjuctions are intersections (overlap)

    disjunctions are unions (whole thing)
  36. If______, then_______
    if hypothesis, then conclusion
  37. converse
    switches the hypothesis & conclusion in conditional
  38. Inverse
    negate both hypothesis and conclusion in conditional
  39. Contrapositve
    Negate and Switch hypothesis and conclusion

    OR negate hypothesis and conclusion of the converse
  40. deductive reasoning
    using rules to make a conclusion
  41. Law of Detachment
    if conditional is true and hypothesis is true, then conclusion is true
  42. Law of Syllogism
    if p-> q and q->r are true, then p->r is true.
  43. if mp definition, then....
  44. if mp theorem, then...q
Card Set
Geometry Definitions
definitions up to chapter 2