Question 251946
I must do a proof. There are 2 triangles. one on top of the other only the top one is upside down. My given is segment AB is parallel to segment CD. those being the bases of each triangle. I must prove the top triangle APB is similar to the lower triangle DPC. the 2 triangles are sitting tip to tip not covering each other at all. face to face if u want to call it that thanks for your help
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The angles at the tip are vertical angles and are equal to one another.
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The line segment joining the parallel lines are transversals so the 
alternate interior angles are equal.
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Three angles of one triangle are equal to three angles in the other.
The triangles are similar by AAA.
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Hope that helps.
Cheers,
Stan H.