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Prove Line and Angle Theorems




 


Videos and lessons to help High School students learn how to prove theorems about lines and angles. 

Theorems include: vertical angles are congruent; when a transversal crosses parallel lines, alternate interior angles are congruent and corresponding angles are congruent; points on a perpendicular bisector of a line segment are exactly those equidistant from the segment’s endpoints.

Common Core: HSG-CO.C.9

Related Topics:
Common Core (Geometry)

Common Core for Mathematics


Proof-Vertical Angles are Equal
Proving that vertical angles are equal.


Corresponding Angles Converse
If two lines are cut by a transversal and the corresponding angles are congruent, then the lines are parallel.





Proof: Alternate Interior Angles Are Congruent
If two parallel lines are cut by a transversal, then the alternate interior angles are congruent.


Proof: Alternate Interior Angles Converse
If two lines are cut by a transversal and the alternate interior angles are congruent, then the lines are parallel.



 

Proof: Consecutive Interior (Same Side) Angles Are Supplementary
If two parallel lines are cut by a transversal, then the consecutive interior angles are supplementary.


Proof: Consecutive Interior Angles Converse
If two lines are cut by a transversal and the consecutive (same side) interior angles are supplementary, then the lines are parallel.




Proof: Perpendicular Bisector Theorem
If a point is on the perpendicular bisector of a segment, then it is equidistant from the endpoints of the segment.


Proof: Perpendicular Bisector Theorem Converse
If a point is equidistant from the endpoints of a segment, then the point is on the perpendicular bisector of the segment.



 

Rotate to landscape screen format on a mobile phone or small tablet to use the Mathway widget, a free math problem solver that answers your questions with step-by-step explanations.


You can use the free Mathway calculator and problem solver below to practice Algebra or other math topics. Try the given examples, or type in your own problem and check your answer with the step-by-step explanations.


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