Triangle congruence: SSS and SAS
Grade 10 Math Worksheet - Building Confidence

Circle the best answer.
Kira checks two tent flaps. SAS needs the angle between two sides. Which angle of △CHQ is between sides CQ and HQ?
- ∠H
- ∠Q
- ∠C
Luz checks two kite halves. SAS needs the angle between two sides. Which angle of △SUW is between sides SU and SW?
△SUW, not to scale, with its corners labeled and no marks. △SUW, not to scale, with its corners labeled and no marks. S U W Not to scale - ∠W
- ∠S
- ∠U
Milo checks two boat sails. SAS needs the angle between two sides. Which angle of △GVY is between sides VY and GV?
△GVY, not to scale, with its corners labeled and no marks. △GVY, not to scale, with its corners labeled and no marks. G V Y Not to scale - ∠Y
- ∠G
- ∠V
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.
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.
Use this
Two triangles, not to scale. △CHW: CH = 8 cm, HW = 13 cm, CW = 9 cm. △QYS: QS = 9 cm, QY = 8 cm, YS = 13 cm. The matching table under them lists the side rows of △CHW ≅ △QYS: CH ↔ QY, HW ↔ YS, CW ↔ QS.
Pia checks two window panes. The figure gives the sides of △CHW and △QYS. Is △CHW ≅ △QYS?
- 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.
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.
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: GU = 14 cm but DF = 15 cm.
- No: SSS also needs one pair of equal angles.
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?
Two triangles, not to scale, with the two pairs of sides marked. The matching table for △DFG ≅ △VSU has one row per pair of parts, DF ↔ VS and FG ↔ SU ticked. Two triangles, not to scale, with the two pairs of sides marked. The matching table for △DFG ≅ △VSU has one row per pair of parts, DF ↔ VS and FG ↔ SU ticked. triangle DFG ≅ triangle VSU not to scale D F G V S U pair of parts check DF <-> VS FG <-> SU - ∠G ↔ ∠U
- ∠F ↔ ∠S
- ∠D ↔ ∠V
- ∠F ↔ ∠U
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?
Two triangles, not to scale, with the two pairs of sides marked. The matching table for △CHQ ≅ △YWS has one row per pair of parts, HQ ↔ WS and CQ ↔ YS ticked. Two triangles, not to scale, with the two pairs of sides marked. The matching table for △CHQ ≅ △YWS has one row per pair of parts, HQ ↔ WS and CQ ↔ YS ticked. C Q H Y S W triangle CHQ ≅ triangle YWS (not to scale) HQ <-> WS CQ <-> YS - ∠Q ↔ ∠S
- ∠H ↔ ∠W
- ∠Q ↔ ∠Y
- ∠C ↔ ∠Y
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?
Two triangles, not to scale, with the two pairs of sides marked. The matching table for △GUW ≅ △FDH has one row per pair of parts, GU ↔ FD and GW ↔ FH ticked. Two triangles, not to scale, with the two pairs of sides marked. The matching table for △GUW ≅ △FDH has one row per pair of parts, GU ↔ FD and GW ↔ FH ticked. triangle GUW ≅ triangle FDH not to scale G U W F D H matching table Part Matching part Check GU FD GW FH - ∠U ↔ ∠D
- ∠G ↔ ∠D
- ∠G ↔ ∠F
- ∠W ↔ ∠H
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?
Two triangles, not to scale, with the two pairs of sides marked. The matching table for △QSY ≅ △VCG has one row per pair of parts, SY ↔ CG and QS ↔ VC ticked. Two triangles, not to scale, with the two pairs of sides marked. The matching table for △QSY ≅ △VCG has one row per pair of parts, SY ↔ CG and QS ↔ VC ticked. Q S Y V C G triangle QSY ≅ triangle VCG SY <-> CG (check) QS <-> VC (check) - ∠S ↔ ∠G
- ∠S ↔ ∠C
- ∠Q ↔ ∠V
- ∠Y ↔ ∠G