Question

Please assist me with this two column proof. Part 1A

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Answer 1

Answer is in the step by step explanation

Explanation:

Since we are given parallel lines, we know <BCA is congruent to <DAC because of alternate interior angles

Then AC is congruent to AC, that's reflexive prop

Now we have SAS, so Tri. ABC cong to tri. CDA,

Then you're done

Answer 2

Explanation:

BC = AD Given

<BCA = <CAD Alternate interior angles of parallel lines cut by a transversal.

AC = AC That's the reflexive property. A line is equal to itself

Triangle BCA = Triangle CAD SAS

Notice that the angle is included inside the two lines that define it (the angle). That's a very important consideration when using SAS. SAA doesn't always work. You can draw exceptions. SAS has no exceptions. It always works.