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.

   Luz sketches a kite wing, a triangle with angles of 72° and 41°. What is the size of its third angle, in degrees?

   67
3. 3.

   Milo sketches a ramp as a right triangle. One of its other angles is 24°. What is the third angle, in degrees?

   66
4. 4.

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

   52
5. 5.

   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
6. 6.

   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?

   • No: a triangle needs all three straws the same length
   • Yes: the two shorter straws reach 13 cm, as far as the longest, so they fit and a triangle forms
   • No: the two shorter straws together (13 cm) are not longer than the longest (13 cm)
7. 7.

   Zee cuts three straws to stand in a water glass. They are 14 cm, 9 cm and 7 cm long. Can the three straws make a triangle?

   • No: the straws are all different lengths
   • No: a triangle needs two straws of the same length, and these straws differ in length
   • Yes: the two shorter straws together (16 cm) are longer than the longest (14 cm)
8. 8.

   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?

   • No: a triangle needs all three straws the same length
   • No: the two shorter straws together (13 cm) are not longer than the longest (18 cm)
   • Yes: any three straws make a triangle
9. 9.

   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?

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