Can three lengths make a triangle?
Grade 8 Math Worksheet

Circle the best answer, or write your answer on the line.
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
- 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
- No: 2.6 + 4.9 = 7.5 cm exactly, so they lie flat
Jun has three crayons: 5.8 cm, 9.5 cm and 3.7 cm. Can they make a triangle?
Labeled sketch, not to scale: the 9.5 cm crayon is the base; the 3.7 cm and 5.8 cm crayons swing up from its ends. Labeled sketch, not to scale: the 9.5 cm crayon is the base; the 3.7 cm and 5.8 cm crayons swing up from its ends. crayons 9.5 cm 3.7 cm 5.8 cm the 9.5 cm crayon is the base; the 3.7 cm and 5.8 cm crayons swing up from its ends Not to scale. - 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: any three crayons make a triangle
- Yes: 9.5 + 3.7 = 13.2 cm, longer than 5.8 cm
Milo has two pieces of yarn, 2.7 cm and 6.2 cm, for two sides of a triangle. The third side is more than ? cm and less than ? cm. Type both numbers, smaller first.
Labeled sketch, not to scale: the 2.7 cm and 6.2 cm pieces of yarn meet at one corner; the third side is marked ? cm. Labeled sketch, not to scale: the 2.7 cm and 6.2 cm pieces of yarn meet at one corner; the third side is marked ? cm. Labeled sketch 2.7 cm 6.2 cm ? cm Not to scale. 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.
Labeled sketch, not to scale: the 4.6 cm and 9.5 cm paper strips meet at one corner; the third side is marked ? cm. Labeled sketch, not to scale: the 4.6 cm and 9.5 cm paper strips meet at one corner; the third side is marked ? cm. 9.5 cm 4.6 cm ? cm Not to scale. 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.
Labeled sketch, not to scale: the 2.5 cm and 10 cm paper strips meet at one corner; the third side is marked ? cm. Labeled sketch, not to scale: the 2.5 cm and 10 cm paper strips meet at one corner; the third side is marked ? cm. 2.5 cm 10 cm ? cm Not to scale. Ren has 4.5 cm and 7.2 cm paper strips for two sides of a triangle. Which length can the third side be?
Labeled sketch, not to scale: the 4.5 cm and 7.2 cm paper strips meet at one corner; the third side is marked ? cm. Labeled sketch, not to scale: the 4.5 cm and 7.2 cm paper strips meet at one corner; the third side is marked ? cm. 7.2 cm 4.5 cm ? cm Not to scale. - 12.4 cm
- 6.3 cm
- 11.7 cm
- 2.1 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?
Labeled sketch, not to scale: the 3.6 cm and 8.4 cm pieces of yarn meet at one corner; the third side is marked ? cm. Labeled sketch, not to scale: the 3.6 cm and 8.4 cm pieces of yarn meet at one corner; the third side is marked ? cm. 3.6 cm 8.4 cm ? cm Not to scale. - 12.5 cm
- 4.8 cm
- 10.5 cm
- 3.9 cm
Ari has paper strips of 3.4 cm and 6.9 cm for two sides of a triangle. The third side is a whole number of cm. What is the longest it can be?
Labeled sketch, not to scale: the 3.4 cm and 6.9 cm paper strips meet at one corner; the third side is marked ? cm. Labeled sketch, not to scale: the 3.4 cm and 6.9 cm paper strips meet at one corner; the third side is marked ? cm. 6.9 cm 3.4 cm ? cm Not to scale. Bo has pieces of yarn of 5.6 cm and 8.7 cm for two sides of a triangle. The third side is a whole number of cm. What is the longest it can be?
Labeled sketch, not to scale: the 5.6 cm and 8.7 cm pieces of yarn meet at one corner; the third side is marked ? cm. Labeled sketch, not to scale: the 5.6 cm and 8.7 cm pieces of yarn meet at one corner; the third side is marked ? cm. 5.6 cm 8.7 cm ? cm Not to scale. 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?
Labeled sketch, not to scale: the 2.2 cm and 9.5 cm paper strips meet at one corner; the third side is marked ? cm. Labeled sketch, not to scale: the 2.2 cm and 9.5 cm paper strips meet at one corner; the third side is marked ? cm. 9.5 cm 2.2 cm ? cm Not to scale.