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8th grade Matching sides and angles of congruent figures worksheet

6 printable versionsChallenge Me10 questions · answer keyFree · no account

Level: Building Confidence · On Level · Challenge Me

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Matching sides and angles of congruent figures

Grade 8 Math Worksheet - Challenge Me

NameDate

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

  1. Ari knows quadrilateral FGHJ is congruent to quadrilateral PQRS, with F↔R, G↔S, H↔P and J↔Q. What is the size of angle Q?

  2. Bo knows quadrilateral ABCD is congruent to quadrilateral WXYZ, with A↔Y, B↔Z, C↔W and D↔X. What is the size of angle X?

  3. Jun knows quadrilateral FGHJ is congruent to quadrilateral PQRS, with F↔Q, G↔R, H↔S and J↔P. What is the size of angle Q?

  4. Luz knows triangle ABC is congruent to triangle ZXY, with A↔Z, B↔X and C↔Y. What is the perimeter of triangle ZXY?

  5. Milo knows triangle ABC is congruent to triangle QRS, with A↔S, B↔Q and C↔R. What is the perimeter of triangle QRS?

  6. Noah knows triangle ABC is congruent to triangle MNP, with A↔N, B↔P and C↔M. What is the perimeter of triangle MNP?

  7. Pia asks whether a slide, flip or turn can put triangle P exactly onto triangle Q. Is that possible?

    • Yes: the sides match in pairs (6 and 6, 8 and 8, 10 and 10).
    • No: no angles are given, so nobody can tell.
    • No: Q looks like P flipped over, which changes the triangle.
    • No: the first sides listed, 6 cm and 10 cm, are different.
  8. Ren asks whether a slide, flip or turn can put triangle P exactly onto triangle Q. Is that possible?

    • Yes: the triangles have the same shape, so one fits on the other.
    • No: the angles match, but Q's sides are twice as long as P's.
    • Yes: sliding Q over P lines up the sides.
    • Yes: all three angles match in pairs.
  9. Tala asks whether a slide, flip or turn can put triangle P exactly onto triangle Q. Is that possible?

    • Yes: sliding Q onto P lines up the third sides.
    • No: the third sides differ, 12 cm and 13 cm.
    • Yes: two pairs of sides match, 7 and 9.
    • Yes: the sides differ by only 1 cm, so one fits on the other.
  10. Zee asks whether a slide, flip or turn can put triangle P exactly onto triangle Q. Is that possible?

    • No: Q looks like P flipped over, which changes the triangle.
    • No: the first angles listed, 50° and 60°, are different.
    • No: the third angle and two sides are not given, so nobody can tell.
    • Yes: two angles and the side between them match, which fixes the whole triangle.
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8th grade Matching sides and angles of congruent figures worksheet – printable
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About this worksheet

Matching sides and angles of congruent figures. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can find a slanted side's length on a grid with the Pythagorean theorem and know that a flip, turn or slide keeps it.
  • I can use a list of matching corners (not in alphabet order) to pair sides and angles, and solve for an unknown in a match.
  • I can say whether two shapes can be congruent from the moves or from all their lengths and angles.

Standard: 8.G.A.2 (partial: congruent figures; describing the sequence of moves is row 33), 8.G.A.1a–b (partial: lengths and angles stay equal)

Words to know

congruent: Same shape and same size; one fits exactly on the other.

matching (corresponding) corners: The corners that land on each other when one shape is laid on the other.

matching sides / angles: A side joins two matching corners; an angle sits at a matching corner. They are equal.

image: The shape after a move. Its corners are named with a prime, A′.

dilation: A move that changes every length by the same factor.

Common mistakes

Your child added the two legs of the slanted side instead of using the Pythagorean theorem. The slanted side is shorter than the two legs added.

Your child stopped at the sum of the squares. The sum is the square of the length, so the last step is the square root.

Your child gave the run or the rise as the length of the slanted side. The slanted side is longer than either leg.

Questions parents ask

What is the most common mistake with matching sides and angles of congruent figures?

Your child added the two legs of the slanted side instead of using the Pythagorean theorem. The slanted side is shorter than the two legs added.

Are these 8th grade math worksheets free to print?

Yes. All 6 printable versions at each level are free to print, with the answer key, and no account is needed.

More grade 8 math

See all grade 8 math

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