Zach tried to solve an equation step by step. \begin{aligned} \dfrac34&=z-\dfrac12 \dfrac34+\dfrac12&=z-\dfrac12+\ dfrac12&\green{\text{Step } 1} \dfrac54&=z&\blue{\text{Ste p } 2} \end{aligned}
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=z−
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=z−
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=z
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Step 1
Step 2
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Find Zach's mistake.
Choose 1

Given: ab ≅ cd and ad ≅ bc prove: abcd is a parallelogram. statements reasons 1. ab ≅ cd; ad ≅ bc 1. given 2. ac ≅ ac 2. reflexive property 3. △adc ≅ △cba 3. ? 4. ∠dac ≅ ∠bca; ∠acd ≅ ∠cab 4. cpctc 5. ∠dac and ∠bca are alt. int. ∠s; ∠acd and ∠cab are alt. int. ∠s 5. definition of alternate interior angles 6. ab ∥ cd; ad ∥ bc 6. converse of the alternate interior angles theorem 7. abcd is a parallelogram 7. definition of parallelogram what is the missing reason in step 3? triangle angle sum theorem sas congruency theorem sss congruency theorem cpctc