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Proof: Parallel Lines Cut by a Transversal (Geometry)

Free printable Geometry geometry worksheet: complete a two-column proof that alternate interior angles are congruent, using the Corresponding Angles Postulate and the Vertical Angles Theorem.

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Geometry Β· Math worksheet
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Geometry Proof: Parallel Lines Cut by a Transversal

Two parallel lines are cut by a transversal. Complete each two-column proof that a pair of alternate interior angles is congruent, using the Corresponding Angles Postulate and the Vertical Angles Theorem.

  1. 1.
    Lines l and m are cut by transversal t, with l βˆ₯ m. Using the standard numbering (angles 1-4 where t crosses l, top-left/top-right/bottom-left/bottom-right in order; angles 5-8 where t crosses m, in the same layout), prove ∠3 β‰… ∠6 (a pair of alternate interior angles). Complete the missing reason in step 4 of the two-column proof.
    lmt12345678
    StatementReason
    1.l βˆ₯ m, and t is a transversal of l and m.Given
    2.∠3 β‰… ∠7.Corresponding Angles Postulate
    3.∠7 β‰… ∠6.Vertical Angles Theorem
    4.∠3 β‰… ∠6.Β 
  2. 2.
    Lines j and k are cut by transversal v, with j βˆ₯ k. Using the standard numbering (angles 1-4 where v crosses j, top-left/top-right/bottom-left/bottom-right in order; angles 5-8 where v crosses k, in the same layout), prove ∠4 β‰… ∠5 (a pair of alternate interior angles). Complete the missing reason in step 4 of the two-column proof.
    jkv12345678
    StatementReason
    1.j βˆ₯ k, and v is a transversal of j and k.Given
    2.∠4 β‰… ∠8.Corresponding Angles Postulate
    3.∠8 β‰… ∠5.Vertical Angles Theorem
    4.∠4 β‰… ∠5.Β 
  3. 3.
    Lines l and m are cut by transversal t, with l βˆ₯ m. Using the standard numbering (angles 1-4 where t crosses l, top-left/top-right/bottom-left/bottom-right in order; angles 5-8 where t crosses m, in the same layout), prove ∠4 β‰… ∠5 (a pair of alternate interior angles). Complete the missing reason in step 1 of the two-column proof.
    lmt12345678
    StatementReason
    1.l βˆ₯ m, and t is a transversal of l and m.Β 
    2.∠4 β‰… ∠8.Corresponding Angles Postulate
    3.∠8 β‰… ∠5.Vertical Angles Theorem
    4.∠4 β‰… ∠5.Transitive Property of Congruence
  4. 4.
    Lines j and k are cut by transversal v, with j βˆ₯ k. Using the standard numbering (angles 1-4 where v crosses j, top-left/top-right/bottom-left/bottom-right in order; angles 5-8 where v crosses k, in the same layout), prove ∠4 β‰… ∠5 (a pair of alternate interior angles). Complete the missing statement in step 3 of the two-column proof.
    jkv12345678
    StatementReason
    1.j βˆ₯ k, and v is a transversal of j and k.Given
    2.∠4 β‰… ∠8.Corresponding Angles Postulate
    3.Β Vertical Angles Theorem
    4.∠4 β‰… ∠5.Transitive Property of Congruence
  5. 5.
    Lines l and m are cut by transversal t, with l βˆ₯ m. Using the standard numbering (angles 1-4 where t crosses l, top-left/top-right/bottom-left/bottom-right in order; angles 5-8 where t crosses m, in the same layout), prove ∠4 β‰… ∠5 (a pair of alternate interior angles). Complete the missing statement in step 1 of the two-column proof.
    lmt12345678
    StatementReason
    1.Β Given
    2.∠4 β‰… ∠8.Corresponding Angles Postulate
    3.∠8 β‰… ∠5.Vertical Angles Theorem
    4.∠4 β‰… ∠5.Transitive Property of Congruence
  6. 6.
    Lines l and m are cut by transversal t, with l βˆ₯ m. Using the standard numbering (angles 1-4 where t crosses l, top-left/top-right/bottom-left/bottom-right in order; angles 5-8 where t crosses m, in the same layout), prove ∠3 β‰… ∠6 (a pair of alternate interior angles). Complete the missing statement in step 1 of the two-column proof.
    lmt12345678
    StatementReason
    1.Β Given
    2.∠3 β‰… ∠7.Corresponding Angles Postulate
    3.∠7 β‰… ∠6.Vertical Angles Theorem
    4.∠3 β‰… ∠6.Transitive Property of Congruence
  7. 7.
    Lines p and q are cut by transversal n, with p βˆ₯ q. Using the standard numbering (angles 1-4 where n crosses p, top-left/top-right/bottom-left/bottom-right in order; angles 5-8 where n crosses q, in the same layout), prove ∠3 β‰… ∠6 (a pair of alternate interior angles). Complete the missing reason in step 3 of the two-column proof.
    pqn12345678
    StatementReason
    1.p βˆ₯ q, and n is a transversal of p and q.Given
    2.∠3 β‰… ∠7.Corresponding Angles Postulate
    3.∠7 β‰… ∠6.Β 
    4.∠3 β‰… ∠6.Transitive Property of Congruence
  8. 8.
    Lines j and k are cut by transversal v, with j βˆ₯ k. Using the standard numbering (angles 1-4 where v crosses j, top-left/top-right/bottom-left/bottom-right in order; angles 5-8 where v crosses k, in the same layout), prove ∠4 β‰… ∠5 (a pair of alternate interior angles). Complete the missing reason in step 2 of the two-column proof.
    jkv12345678
    StatementReason
    1.j βˆ₯ k, and v is a transversal of j and k.Given
    2.∠4 β‰… ∠8.Β 
    3.∠8 β‰… ∠5.Vertical Angles Theorem
    4.∠4 β‰… ∠5.Transitive Property of Congruence
  9. 9.
    Lines l and m are cut by transversal t, with l βˆ₯ m. Using the standard numbering (angles 1-4 where t crosses l, top-left/top-right/bottom-left/bottom-right in order; angles 5-8 where t crosses m, in the same layout), prove ∠4 β‰… ∠5 (a pair of alternate interior angles). Complete the missing reason in step 3 of the two-column proof.
    lmt12345678
    StatementReason
    1.l βˆ₯ m, and t is a transversal of l and m.Given
    2.∠4 β‰… ∠8.Corresponding Angles Postulate
    3.∠8 β‰… ∠5.Β 
    4.∠4 β‰… ∠5.Transitive Property of Congruence
  10. 10.
    Lines p and q are cut by transversal n, with p βˆ₯ q. Using the standard numbering (angles 1-4 where n crosses p, top-left/top-right/bottom-left/bottom-right in order; angles 5-8 where n crosses q, in the same layout), prove ∠4 β‰… ∠5 (a pair of alternate interior angles). Complete the missing statement in step 1 of the two-column proof.
    pqn12345678
    StatementReason
    1.Β Given
    2.∠4 β‰… ∠8.Corresponding Angles Postulate
    3.∠8 β‰… ∠5.Vertical Angles Theorem
    4.∠4 β‰… ∠5.Transitive Property of Congruence
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