Prove that the opposite angles of a parallelogram are congruent. http://learn.flvs.net/webdav/assessment_images/educator_geometry_v14/pool_Geom_3641_1004_04/image0154e985306.gif
@J.L. take triangle ABC and ADC here we know that AC= AC ( common side) AB= CD ( opposite sides of a parallelogram are equal) BC=AD (-same-) so triangle ABC= triangle ADC do you get this?
I think I have to write a paragraph proof. I thought we would write something about the vertical angle theorem...
So would I start the proof as: It is given that quadrilateral ABCD is a parallelogram. Using the Reflexive Property, we know that line AC is congruent to line AC.
yeah, doing good:)
Line AB is congruent to line CD because opposite sides of a parallelogram are equal. Line BC is equal to line AD because both pairs of opposite sides of a parallelogram are congruent and parallel. Therefore, triangle ABC is congruent to triangle ADC.
@ash2326
yeah you're correct:D
So the last sentence would be: opposite angles of a parallelogram are congruent using CPCTC?
yeah:D angle ABC= angle ADC using CPCTC
Thank you so much!
welcome:D
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