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10th grade Triangle congruence: SSS and SAS worksheet

6 printable versionsBuilding Confidence10 questions · answer keyFree · no account

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Triangle congruence: SSS and SAS

Grade 10 Math Worksheet - Building Confidence

NameDate

Circle the best answer.

  1. Kira checks two tent flaps. SAS needs the angle between two sides. Which angle of △CHQ is between sides CQ and HQ?

    • ∠C
    • ∠H
    • ∠Q
  2. Luz checks two kite halves. SAS needs the angle between two sides. Which angle of △SUW is between sides SU and SW?

    • ∠W
    • ∠U
    • ∠S
  3. Milo checks two boat sails. SAS needs the angle between two sides. Which angle of △GVY is between sides VY and GV?

    • ∠V
    • ∠Y
    • ∠G
  4. Read this first

    Use this

    Two triangles, not to scale. △DFG: DF = 7 cm, FG = 10 cm, DG = 12 cm. △SUV: SV = 12 cm, SU = 7 cm, UV = 10 cm. The matching table under them lists the side rows of △DFG ≅ △SUV: DF ↔ SU, FG ↔ UV, DG ↔ SV.

  5. Noah checks two sandwich halves. The figure gives the sides of △DFG and △SUV. Is △DFG ≅ △SUV?

    • No: SSS also needs one pair of equal angles.
    • No: the sides are listed in a different order.
    • Yes, by SSS: all three pairs of sides are equal.
  6. Use this

    Two triangles, not to scale. △GQU: GQ = 11 cm, QU = 6 cm, GU = 14 cm. △DCF: DF = 15 cm, DC = 11 cm, CF = 6 cm. The matching table under them lists the side rows of △GQU ≅ △DCF: GQ ↔ DC, QU ↔ CF, GU ↔ DF.

  7. Ren checks two paper triangles. The figure gives the sides of △GQU and △DCF. Is △GQU ≅ △DCF?

    • Yes, by SSS: GQ and QU match their partners.
    • No: SSS also needs one pair of equal angles.
    • No: GU = 14 cm but DF = 15 cm.
  8. Two triangles, not to scale. Tala checks two rug triangles. The figure gives the sides of △SVY and △HWG. Is △SVY ≅ △HWG?

    • Yes, by SSS: SV and SY match their partners.
    • No: VY = 12 cm but WG = 11 cm.
    • No: SSS also needs one pair of equal angles.
  9. Zee checks two kite halves, △DFG and △VSU. The matching table has ✓ on DF ↔ VS and FG ↔ SU. Which angle row needs a ✓ for SAS?

    • ∠F ↔ ∠U
    • ∠G ↔ ∠U
    • ∠D ↔ ∠V
    • ∠F ↔ ∠S
  10. Ari checks the two sides of a stepladder, △CHQ and △YWS. The matching table has ✓ on HQ ↔ WS and CQ ↔ YS. Which angle row needs a ✓ for SAS?

    • ∠H ↔ ∠W
    • ∠Q ↔ ∠S
    • ∠C ↔ ∠Y
    • ∠Q ↔ ∠Y
  11. Bo checks two boat sails, △GUW and △FDH. The matching table has ✓ on GU ↔ FD and GW ↔ FH. Which angle row needs a ✓ for SAS?

    • ∠G ↔ ∠D
    • ∠W ↔ ∠H
    • ∠G ↔ ∠F
    • ∠U ↔ ∠D
  12. Esme checks two bike-frame triangles, △QSY and △VCG. The matching table has ✓ on SY ↔ CG and QS ↔ VC. Which angle row needs a ✓ for SAS?

    • ∠Q ↔ ∠V
    • ∠S ↔ ∠G
    • ∠S ↔ ∠C
    • ∠Y ↔ ∠G
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10th grade Triangle congruence: SSS and SAS worksheet – printable
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About this worksheet

Triangle congruence: SSS and SAS. Every version has 10 questions, and the answer key prints on the second page.

What your child will learn

  • I can say which angle is between two sides, and tell SAS from SSA.
  • I can decide whether the facts given prove two triangles congruent by SSS or SAS.
  • I can find the missing fact or the value of x that makes SSS or SAS work, including a side two triangles share.

Standard: G-CO.B.8

Words to know

SSS: Three pairs of equal sides prove two triangles congruent.

SAS: Two pairs of sides and the angle between them prove it.

included angle: The angle where two sides meet; its letter is in both side names.

SSA: Two sides and an angle not between them: not a rule, proves nothing.

shared side: One segment that belongs to both triangles; it matches itself.

vertical angles: Angles across from each other where two lines cross; always equal.

Common mistakes

Your child used an angle that is not between the two sides.

Your child thought three pairs of equal sides were not enough. Build two triangles from the same three straws and see they always match.

Your child checked two pairs of sides and stopped.

What to say

Ask: at which corner do the two sides meet?

Ask: does SSS need two pairs or three?

Questions parents ask

What is the most common mistake with triangle congruence: sss and sas?

Your child used an angle that is not between the two sides.

How can I help my child with triangle congruence: sss and sas?

Ask: at which corner do the two sides meet?

Are these 10th 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 geometry

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