This document provides definitions and descriptions of basic geometry terms including: - Points, lines, line segments, rays, intersecting lines, perpendicular and parallel lines - Angles and angle types such as acute, obtuse, right, straight, complementary, supplementary - Triangles defined by angles and sides including right, obtuse, acute, scalene, isosceles, equilateral - Quadrilaterals including trapezoids, parallelograms, rectangles, rhombuses, and squares - Circles and circle terms such as chords, diameters, arcs, radii, sectors, circumference, and area

1. Lines Angles Triangles Quadrilaterals Circles Geometry Guide

2. lines Points Line Segments Ray Lines Intersecting Perpendicular Parallel Skew Lines

3. Points A point is a precise location in space. It is labled with a letter. Point M Point L Points

4. ' A line that starts one place and ends at another. Point A Point M Line Segments

5. ' Starts one place and goes on for who knows. Ray

6. ' A line is something that goes on forever. Lines

7. Intersecting Two lines that meet in the middle. Intersecting

8. ' Lines that meet in the middle and make right angles. Perpendicular

9. ' Two lines next to each other but never intersect Parallel

10. ' Lines that are in the same plane but never meet. Skew

11. . Acute Obtuse Right Vertex/Vertices Complementary Supplementary Vertical/Opposite Adjacent Angles

12. . An acute is an angle that is less then 90 degrees Acute Angle

13. . An obtuse is an angle that is more then 90 degrees Obtuse Angle

14. . An angle at exactly 90 degrees. Right Angle

15. . A straight angle is two 90 degrees it is 180 degrees Straight Angle

16. . The dot where two lines in an angle meet Vertex/ Vertices

17. . Two angles are complementary if the sum measures to 90 degrees. 50 deg 40 deg Complementary

18. . When you add the angles to 180 degrees. 180 degrees Supplementary

19. . Angles that are vertical to each other Vertical / Opposite

20. . Angles that are right next to each other Adjacent

21. . Right Obtuse Acute Scalene Isosceles Equilateral Sum of internal angles Perimeter Area Triangles

22. A triangle with the bigger angle a right angle Right

23. A triangle with the bigger angle being obtuse Obtuse

24. Acute A triangle with the greater angle an acute Acute

25. A triangle with no congruent sides Scalene

26. A triangle with two congruent sides Isosceles

27. All sides are congruent Equilateral

28. Sum of Internal Angles

29. The outside of a shape added together 90 90 50 50 50 +50 +90 +90= 280 Perimeter

30. The inside amount of a shape. 20 30 Area

31. Quadrilaterals Quadrilateral Trapezoid Parallelogram Rectangle Rhombus Square Area of Rectangle Area of square Area of Parallelogram Area of trapezoid

32. Quadrilateral A four sided figure.

33. Trapezoid A quadrilateral with two parallel lines

34. Parallelogram Opposite sides are parallel and congruent

35. Rectangle Parallelogram with four right angles

36. Rhombus A parallelogram with two congruent sides.

37. Square Rectangle with four congruent sides

38. Area of a rectangle Length times height

39. Area of a Square Length times height

40. Area of a Parallelogram Length times height divided by half

41. Area of a Trapezoid Height times length divided by half

42. Circles Chord Diameter arc Radius Sector Circumfrence Area of a Circle Other Polygons

43. Chord A line segment with two points on the circle

44. Diameter A line segment that passes through the center of the circle

45. Arc A part of a circle

46. Radius With one end point in the middle and the other on th edge

47. Sector A region enclosed by two radii and the arc

48. Circumference Area of the circle

49. Area of a circle The circumference is the area

50. Polygons are shapes Other Polygons