Can three lengths make a triangle?
Grade 8 Math Worksheet
Circle the best answer, or write your answer on the line.
Bo has three pieces of yarn: 12 cm, 7.5 cm and 5.5 cm. Can they make a triangle?
- No: a triangle needs three equal sides to join up
- No: 12 cm is longer than 5.5 cm
- Yes: 5.5 + 7.5 = 13 cm, longer than 12 cm
Esme has three paper strips: 2.6 cm, 7.5 cm and 4.9 cm. Can they make a triangle?
- Yes: any three paper strips make a triangle
- No: 2.6 + 4.9 = 7.5 cm exactly, so they lie flat
- Yes: 7.5 + 2.6 = 10.1 cm, longer than 4.9 cm
- Yes: 2.6 + 4.9 is not shorter than 7.5 cm
Jun has three crayons: 5.8 cm, 9.5 cm and 3.7 cm. Can they make a triangle?
- No: 3.7 + 5.8 = 9.5 cm exactly, so they lie flat
- Yes: 3.7 + 5.8 is not shorter than 9.5 cm
- Yes: 9.5 + 3.7 = 13.2 cm, longer than 5.8 cm
- Yes: any three crayons make a triangle
Kira has three pencils: 8 cm, 3.2 cm and 4.5 cm. Can they make a triangle?
- Yes: 8 + 3.2 = 11.2 cm, longer than 4.5 cm
- Yes: any three pencils make a triangle
- No: they lie flat, with nothing left over
- No: 3.2 + 4.5 = 7.7 cm, shorter than 8 cm
Noah has two paper strips, 4.6 cm and 9.5 cm, for two sides of a triangle. The third side is more than ? cm and less than ? cm. Type both numbers, smaller first.
Pia has two paper strips, 2.5 cm and 10 cm, for two sides of a triangle. The third side is more than ? cm and less than ? cm. Type both numbers, smaller first.
Ren has 4.5 cm and 7.2 cm paper strips for two sides of a triangle. Which length can the third side be?
- 6.3 cm
- 2.1 cm
- 12.4 cm
- 11.7 cm
Tala has 3.6 cm and 8.4 cm pieces of yarn for two sides of a triangle. Which length can the third side be?
- 12.5 cm
- 3.9 cm
- 10.5 cm
- 4.8 cm
Zee has 2.8 cm and 6.5 cm paper strips for two sides of a triangle. Which length can the third side be?
- 3.5 cm
- 9.8 cm
- 4 cm
- 9.3 cm
Esme has paper strips of 2.2 cm and 9.5 cm for two sides of a triangle. The third side is a whole number of cm. What is the longest it can be?