Angles and sides of triangles

Answer Key - Grade 6 Math Worksheet

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

1. 1.

   Esme sketches a flower bed, a triangle with angles of 55° and 65°. What is the size of its third angle, in degrees?

   60
2. 2.

   Noah sketches a sled ramp as a right triangle. One of its other angles is 38°. What is the third angle, in degrees?

   52
3. 3.

   Pia sketches a ladder against a wall as a right triangle. One of its other angles is 62°. What is the third angle, in degrees?

   28
4. 4.

   Tala cuts three straws to stand in a water glass. They are 13 cm, 6 cm and 7 cm long. Can the three straws make a triangle?

   • Yes: the two shorter straws reach 13 cm, as far as the longest, so they fit and a triangle forms
   • No: a triangle needs all three straws the same length
   • No: the two shorter straws together (13 cm) are not longer than the longest (13 cm)
5. 5.

   Ari cuts three straws to stand in a water glass. They are 18 cm, 5 cm and 8 cm long. Can the three straws make a triangle?

   • Yes: any three straws make a triangle
   • No: the two shorter straws together (13 cm) are not longer than the longest (18 cm)
   • No: a triangle needs all three straws the same length
6. 6.

   Bo cuts three straws to stand in a water glass. They are 12 cm, 5 cm and 7 cm long. Can the three straws make a triangle?

   • No: a triangle needs all three straws the same length
   • Yes: the two shorter straws reach 12 cm, as far as the longest, so they fit and a triangle forms
   • No: the two shorter straws together (12 cm) are not longer than the longest (12 cm)
7. 7.

   The lengths in each set are the ones listed in the choices. Esme sorts straws into three sets next to a water glass. Which set can make a triangle?

   • 4 cm, 5 cm and 9 cm
   • 2 cm, 3 cm and 8 cm
   • 6 cm, 7 cm and 10 cm
8. 8.

   Tala draws triangle PQR on a map. Side QR is 6 cm, side RP is 8 cm and side PQ is 11 cm. Which corner has the largest angle?

   • Corner P, at one end of the 11 cm side
   • Corner Q, at one end of the 11 cm side
   • Corner R, across from the 11 cm side
9. 9.

   Zee draws triangle PQR on a map. Side QR is 12 cm, side RP is 7 cm and side PQ is 9 cm. Which corner has the largest angle?

   • Corner R, at one end of the 12 cm side
   • Corner P, across from the 12 cm side
   • Corner Q, at one end of the 12 cm side
10. 10.

    Ari draws triangle PQR on a map. Side QR is 5 cm, side RP is 13 cm and side PQ is 10 cm. Which corner has the largest angle?

    • Corner R, at one end of the 13 cm side
    • Corner Q, across from the 13 cm side
    • Corner P, at one end of the 13 cm side