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February 10, 2014. D. E. Aim: Let’s do CPCTC. Find out what it means to me. Given: Rectangle CDEF Prove: Triangle CDF is congruent to Triangle EFD. F. C. Recap: Proofs. Make statements that are supported by valid reasons
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February 10, 2014 D E Aim: Let’s do CPCTC. Find out what it means to me. Given: Rectangle CDEF Prove: Triangle CDF is congruent to Triangle EFD F C
Recap: Proofs • Make statements that are supported by valid reasons • Statements should start off coming from what was given (break it down, why did they give me that specific information) and then by viewing the diagram • Do not assume anything about a picture
Important Phrases • What are some things that if we see, we know has to be referring to a midpoint? • What are some things that if we see on the diagram (using no information other than what we see), we know we can make a new congruency statement? • What are some things parallel lines can give us? • What can perpendicular lines give us? • What things, by definition, are perpendicular?
Practice 1 Given: AB = CD AC is the perpendicular bisector of BD A B Prove: Triangle ABE = Triangle CDE E D C
CPCTC • Looking back at our last diagram, having already shown the two triangles are congruent, what do we think we can say about the remaining parts of those triangles?
Using CPCTC • Remember: CPCTC relies on the CT. We cannot use it until we show the triangles are congruent! B Given: CA bisects angle DAB / BCA = / DCA Prove: AB = AD A C D
February 11, 2014 D E Aim: Proof Review / Special Cases and Regents Questions Given: Rectangle CDEF CA = BE Prove: Triangle EAD is congruent to Triangle CBF A B F C
D E Given: Rectangle CDEF CA = BE Prove: Triangle EAD is congruent to Triangle CBF A B F C
More? You want…MORE? From June 2012:
For the remainder of the period: • You may work alone or in groups on the homeworkOR • You may discuss last night’s homework with each other / with me TONIGHT’S HW: Packet section 4-6 (all)