Which angle pairs prove that two lines are parallel?

Grade 10 Math Worksheet - Challenge Me

NameDate

Circle the best answer, or write your answer on the line.

  1. Luz draws two lines on paper. m∠DGH = (3x + 5)° and m∠GHQ = (2x + 25)°. What value of x makes DF ∥ QS?

  2. Milo checks two bike lanes. m∠UGF = (4x − 10)° and m∠SHV = (x + 35)°. What value of x makes DF ∥ QS?

    Use the picture in question 1.

  3. Noah checks two stripes on a rug. m∠FGH = (6x + 4)° and m∠GHS = (2x + 16)°. What value of x makes DF ∥ QS?

    Use the picture in question 1.

  4. Zee's window is quadrilateral PQRS with PQ ∥ SR and PS ∥ QR. Diagonal PR has m∠QPR = 38° and m∠PRQ = 41°. What is m∠P?

  5. Ari's rug is quadrilateral PQRS with PQ ∥ SR and PS ∥ QR. Diagonal PR has m∠QPR = 25° and m∠PRQ = 52°. What is m∠P?

    Use the picture in question 4.

  6. Bo's map tile is quadrilateral PQRS with PQ ∥ SR and PS ∥ QR. Diagonal PR has m∠QPR = 33° and m∠PRQ = 49°. What is m∠S?

    Use the picture in question 4.

  7. Esme's paper is quadrilateral PQRS with PQ ∥ SR and PS ∥ QR. Diagonal PR has m∠QPR = 36° and m∠PRQ = 44°. SR is extended past R to T. What is m∠QRT?

    Use the picture in question 4.

  8. Jun measures corresponding angles where line t crosses lines l, m and n: 68° at l, 68° at m and 71° at n. Which statement is justified?

    • l ∥ m, since their corresponding angles are both 68°, while n is parallel to neither
    • l ∥ n, since 71° at n and its supplement 109° add to 180°, which is the test for parallel lines
    • No two lines are parallel: corresponding angles must add to 180°, and 68° + 68° does not equal 180°
    • m ∥ n, since their angles, 68° and 71°, differ by just 3°, which is close enough to be equal
  9. Kira can use one given to prove DF ∥ QS. Which given is enough?

    • m∠UGF = 72° and m∠FGH = 108°, a linear pair that adds to 180°
    • m∠FGH = 112° and m∠GHS = 112°, same-side interior angles that are congruent
    • m∠DGH = 68° and m∠GHS = 112°, alternate interior angles that add to 180°
    • m∠FGH = 112° and m∠GHQ = 112°, alternate interior angles that are congruent
  10. Luz writes: 1. Assume DF ∥ QS. 2. Then alternate interior angles are congruent. 3. So m∠DGH = m∠GHS. 4. So DF ∥ QS. What is wrong?

    Use the picture in question 9.

    • Step 2 should name corresponding angles, since ∠DGH and ∠GHS are corresponding angles here
    • Step 3 is wrong: alternate interior angles between parallel lines are supplementary, not congruent
    • Step 1 assumes the conclusion; the proof must start from the congruent angles and use the converse
    • Nothing is wrong: Step 2 is a correct theorem, and Step 3 follows from it, so the proof holds
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Which angle pairs prove that two lines are parallel?

Answer Key - Grade 10 Math Worksheet - Challenge Me

Circle the best answer, or write your answer on the line.

  1. Luz draws two lines on paper. m∠DGH = (3x + 5)° and m∠GHQ = (2x + 25)°. What value of x makes DF ∥ QS?

    30
  2. Milo checks two bike lanes. m∠UGF = (4x − 10)° and m∠SHV = (x + 35)°. What value of x makes DF ∥ QS?

    Use the picture in question 1.

    31
  3. Noah checks two stripes on a rug. m∠FGH = (6x + 4)° and m∠GHS = (2x + 16)°. What value of x makes DF ∥ QS?

    Use the picture in question 1.

    20
  4. Zee's window is quadrilateral PQRS with PQ ∥ SR and PS ∥ QR. Diagonal PR has m∠QPR = 38° and m∠PRQ = 41°. What is m∠P?

    79 degrees
  5. Ari's rug is quadrilateral PQRS with PQ ∥ SR and PS ∥ QR. Diagonal PR has m∠QPR = 25° and m∠PRQ = 52°. What is m∠P?

    Use the picture in question 4.

    77 degrees
  6. Bo's map tile is quadrilateral PQRS with PQ ∥ SR and PS ∥ QR. Diagonal PR has m∠QPR = 33° and m∠PRQ = 49°. What is m∠S?

    Use the picture in question 4.

    98 degrees
  7. Esme's paper is quadrilateral PQRS with PQ ∥ SR and PS ∥ QR. Diagonal PR has m∠QPR = 36° and m∠PRQ = 44°. SR is extended past R to T. What is m∠QRT?

    Use the picture in question 4.

    100 degrees
  8. Jun measures corresponding angles where line t crosses lines l, m and n: 68° at l, 68° at m and 71° at n. Which statement is justified?

    • l ∥ m, since their corresponding angles are both 68°, while n is parallel to neither
    • l ∥ n, since 71° at n and its supplement 109° add to 180°, which is the test for parallel lines
    • No two lines are parallel: corresponding angles must add to 180°, and 68° + 68° does not equal 180°
    • m ∥ n, since their angles, 68° and 71°, differ by just 3°, which is close enough to be equal
  9. Kira can use one given to prove DF ∥ QS. Which given is enough?

    • m∠UGF = 72° and m∠FGH = 108°, a linear pair that adds to 180°
    • m∠FGH = 112° and m∠GHS = 112°, same-side interior angles that are congruent
    • m∠DGH = 68° and m∠GHS = 112°, alternate interior angles that add to 180°
    • m∠FGH = 112° and m∠GHQ = 112°, alternate interior angles that are congruent
  10. Luz writes: 1. Assume DF ∥ QS. 2. Then alternate interior angles are congruent. 3. So m∠DGH = m∠GHS. 4. So DF ∥ QS. What is wrong?

    Use the picture in question 9.

    • Step 2 should name corresponding angles, since ∠DGH and ∠GHS are corresponding angles here
    • Step 3 is wrong: alternate interior angles between parallel lines are supplementary, not congruent
    • Step 1 assumes the conclusion; the proof must start from the congruent angles and use the converse
    • Nothing is wrong: Step 2 is a correct theorem, and Step 3 follows from it, so the proof holds