← Triangles: angle sum, exterior angle and Pythagoras lesson New set →

Class 7 Maths Worksheet: Triangles

Maths worksheets lesson 53: Triangles: angle sum, exterior angle and Pythagoras · Set 571 · 40 sums
TalentJR

The method (Inside 180, outside the sum): Angle sum: ∠A + ∠B + ∠C = 180°. Exterior angle = sum of the two interior opposite angles. Right-angled triangle: longest side² = side² + side² (3, 4, 5 and 5, 12, 13 are famous sets). Sides can make a triangle only if the two shorter sides add up to more than the longest side.

NameDateTime takenScore ___ / 40
  1. 1.An exterior angle of a triangle is 91°. One of its two interior opposite angles is 54°. What is the other one (in degrees)?
  2. 2.In triangle ABC, angle A = 73° and angle B = 36°. What is angle C (in degrees)?
  3. 3.In a right-angled triangle, one of the other two angles is 44°. What is the third angle (in degrees)?
  4. 4.In triangle ABC, angle A = 39° and angle B = 106°. What is angle C (in degrees)?
  5. 5.In an isosceles triangle, the two equal angles are 34° each. What is the third angle (in degrees)?
  6. 6.In triangle ABC, angle A = 25° and angle B = 103°. What is angle C (in degrees)?
  7. 7.The longest side of a right-angled triangle is 25 cm and one of the other sides is 7 cm. How long is the third side (in cm)?
  8. 8.Can a triangle have sides of 3 cm, 6 cm and 12 cm? (a) Yes (b) No
  9. 9.In triangle ABC, angle A = 58° and angle B = 59°. What is angle C (in degrees)?
  10. 10.In triangle ABC, angle A = 48° and angle B = 68°. What is angle C (in degrees)?
  11. 11.The angles of a triangle are in the ratio 1 : 2 : 6. What is the biggest angle (in degrees)?
  12. 12.In triangle ABC, angle A = 28° and angle B = 107°. What is angle C (in degrees)?
  13. 13.Can a triangle have sides of 13 cm, 11 cm and 8 cm? (a) No (b) Yes
  14. 14.The longest side of a right-angled triangle is 17 cm and one of the other sides is 8 cm. How long is the third side (in cm)?
  15. 15.In a right-angled triangle, one of the other two angles is 40°. What is the third angle (in degrees)?
  16. 16.The two shorter sides of a right-angled triangle are 5 cm and 12 cm. How long is the longest side (in cm)?
  17. 17.The two interior opposite angles of a triangle are 32° and 62°. What is the exterior angle (in degrees)?
  18. 18.Can a triangle have sides of 4 cm, 4 cm and 12 cm? (a) No (b) Yes
  19. 19.Can a triangle have sides of 15 cm, 9 cm and 2 cm? (a) No (b) Yes
  20. 20.In a right-angled triangle, one of the other two angles is 26°. What is the third angle (in degrees)?
  21. 21.The two shorter sides of a right-angled triangle are 15 cm and 8 cm. How long is the longest side (in cm)?
  22. 22.In triangle ABC, angle A = 50° and angle B = 43°. What is angle C (in degrees)?
  23. 23.The angles of a triangle are in the ratio 1 : 1 : 2. What is the biggest angle (in degrees)?
  24. 24.In an isosceles triangle, the two equal angles are 32° each. What is the third angle (in degrees)?
  25. 25.In an isosceles triangle, the two equal angles are 29° each. What is the third angle (in degrees)?
  26. 26.Can a triangle have sides of 5 cm, 5 cm and 7 cm? (a) Yes (b) No
  27. 27.The angles of a triangle are in the ratio 1 : 2 : 3. What is the smallest angle (in degrees)?
  28. 28.The two shorter sides of a right-angled triangle are 24 cm and 7 cm. How long is the longest side (in cm)?
  29. 29.The two shorter sides of a right-angled triangle are 7 cm and 24 cm. How long is the longest side (in cm)?
  30. 30.An exterior angle of a triangle is 120°. One of its two interior opposite angles is 50°. What is the other one (in degrees)?
  31. 31.In a right-angled triangle, one of the other two angles is 69°. What is the third angle (in degrees)?
  32. 32.An exterior angle of a triangle is 92°. One of its two interior opposite angles is 40°. What is the other one (in degrees)?
  33. 33.Can a triangle have sides of 8 cm, 12 cm and 24 cm? (a) Yes (b) No
  34. 34.In a right-angled triangle, one of the other two angles is 80°. What is the third angle (in degrees)?
  35. 35.In a right-angled triangle, one of the other two angles is 20°. What is the third angle (in degrees)?
  36. 36.Can a triangle have sides of 6 cm, 10 cm and 4 cm? (a) No (b) Yes
  37. 37.In triangle ABC, angle A = 64° and angle B = 62°. What is angle C (in degrees)?
  38. 38.In a right-angled triangle, one of the other two angles is 13°. What is the third angle (in degrees)?
  39. 39.Can a triangle have sides of 8 cm, 7 cm and 15 cm? (a) No (b) Yes
  40. 40.Can a triangle have sides of 3 cm, 6 cm and 14 cm? (a) Yes (b) No

Answer key

  1. 37
  2. 71
  3. 46
  4. 35
  5. 112
  6. 52
  7. 24
  8. No
  9. 63
  10. 64
  11. 120
  12. 45
  13. Yes
  14. 15
  15. 50
  16. 13
  17. 94
  18. No
  19. No
  20. 64
  21. 17
  22. 87
  23. 90
  24. 116
  25. 122
  26. Yes
  27. 30
  28. 25
  29. 25
  30. 70
  31. 21
  32. 52
  33. No
  34. 10
  35. 70
  36. No
  37. 54
  38. 77
  39. No
  40. No

Free maths worksheets lessons, practice and worksheets at talentjr.in/maths-worksheets