# Geometry Vocab. Ch.3

geometry vocabulary chapter 3

## Terms

undefined, object

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- Alternate interior angles
- Two non adjacent interior angles on opposite sides of the transversal
- Pentagon
- 5 sides
- Decagon
- 10 sides
- Equilateral triangle
- all sides congruent
- Transversal
- a line that intesects two or more coplanar lines in different points
- Same-side interior angles
- two interior angles on the same side of the transversal
- Ways to prove lines are parallel
- 1.) Show that a pair of corresponding angles are congruent. 2.)Show that a pair of alternate interior angles are congruent. 3.) Show that a pair of same-side interior angles are congruent. 4.) In a plane show that both lines are perpendicular to the third line. 5.)Show that both lines are parallel to a third line
- Triangle
- 3 sides
- Parallel lines
- coplanar lines that do not intersect
- Hexagon
- 6 sides
- n-gon
- n number of sides
- Skew lines
- non-coplanar lines that are not parallel or intersecting
- Inductive Reasoning
- Conclusions bases on several past observations; Conclusion is probably true, but not necessarily true
- Octagon
- 8 sides
- Isosceles Triangle
- At least two sides congruent
- Deductive Reasoning
- Conclusion bases on accepted statemenets(definations, postulates, previous theorems, corollaries, and given information); conclusions must be true if hypothesis is true
- Scalene Triangle
- no sides congruent
- Corresponding angles
- two angles in corresponding positions relative to the two lines
- Quadrilateral
- 4 sides