← 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 704 · 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.The angles of a triangle are in the ratio 2 : 3 : 5. What is the biggest angle (in degrees)?
  2. 2.In triangle ABC, angle A = 84° and angle B = 67°. What is angle C (in degrees)?
  3. 3.An exterior angle of a triangle is 54°. One of its two interior opposite angles is 29°. What is the other one (in degrees)?
  4. 4.The angles of a triangle are in the ratio 5 : 6 : 7. What is the smallest angle (in degrees)?
  5. 5.The two interior opposite angles of a triangle are 66° and 30°. What is the exterior angle (in degrees)?
  6. 6.In triangle ABC, angle A = 38° and angle B = 25°. What is angle C (in degrees)?
  7. 7.Can a triangle have sides of 10 cm, 19 cm and 4 cm? (a) No (b) Yes
  8. 8.The angles of a triangle are in the ratio 2 : 7 : 9. What is the biggest angle (in degrees)?
  9. 9.An exterior angle of a triangle is 75°. One of its two interior opposite angles is 31°. What is the other one (in degrees)?
  10. 10.An exterior angle of a triangle is 109°. One of its two interior opposite angles is 62°. What is the other one (in degrees)?
  11. 11.Can a triangle have sides of 13 cm, 11 cm and 2 cm? (a) Yes (b) No
  12. 12.The two shorter sides of a right-angled triangle are 15 cm and 8 cm. How long is the longest side (in cm)?
  13. 13.In triangle ABC, angle A = 58° and angle B = 21°. What is angle C (in degrees)?
  14. 14.The angles of a triangle are in the ratio 5 : 6 : 7. What is the biggest angle (in degrees)?
  15. 15.The angles of a triangle are in the ratio 1 : 3 : 5. What is the biggest angle (in degrees)?
  16. 16.In an isosceles triangle, the two equal angles are 41° each. What is the third angle (in degrees)?
  17. 17.Can a triangle have sides of 8 cm, 4 cm and 11 cm? (a) No (b) Yes
  18. 18.Can a triangle have sides of 6 cm, 8 cm and 16 cm? (a) No (b) Yes
  19. 19.In a right-angled triangle, one of the other two angles is 17°. What is the third angle (in degrees)?
  20. 20.In triangle ABC, angle A = 66° and angle B = 58°. What is angle C (in degrees)?
  21. 21.The angles of a triangle are in the ratio 1 : 2 : 3. What is the biggest angle (in degrees)?
  22. 22.Can a triangle have sides of 15 cm, 8 cm and 3 cm? (a) Yes (b) No
  23. 23.In triangle ABC, angle A = 24° and angle B = 116°. What is angle C (in degrees)?
  24. 24.An exterior angle of a triangle is 69°. One of its two interior opposite angles is 44°. What is the other one (in degrees)?
  25. 25.In triangle ABC, angle A = 25° and angle B = 72°. What is angle C (in degrees)?
  26. 26.The two interior opposite angles of a triangle are 25° and 27°. What is the exterior angle (in degrees)?
  27. 27.In a right-angled triangle, one of the other two angles is 72°. What is the third angle (in degrees)?
  28. 28.In a right-angled triangle, one of the other two angles is 66°. What is the third angle (in degrees)?
  29. 29.In a right-angled triangle, one of the other two angles is 41°. What is the third angle (in degrees)?
  30. 30.In an isosceles triangle, the two equal angles are 30° each. What is the third angle (in degrees)?
  31. 31.The two shorter sides of a right-angled triangle are 3 cm and 4 cm. How long is the longest side (in cm)?
  32. 32.In an isosceles triangle, the two equal angles are 61° each. What is the third angle (in degrees)?
  33. 33.In triangle ABC, angle A = 67° and angle B = 82°. What is angle C (in degrees)?
  34. 34.Can a triangle have sides of 6 cm, 6 cm and 13 cm? (a) No (b) Yes
  35. 35.In an isosceles triangle, the two equal angles are 60° each. What is the third angle (in degrees)?
  36. 36.In an isosceles triangle, the angle between the two equal sides is 114°. What is each of the other two angles (in degrees)?
  37. 37.The longest side of a right-angled triangle is 13 cm and one of the other sides is 5 cm. How long is the third side (in cm)?
  38. 38.An exterior angle of a triangle is 100°. One of its two interior opposite angles is 77°. What is the other one (in degrees)?
  39. 39.In triangle ABC, angle A = 83° and angle B = 20°. What is angle C (in degrees)?
  40. 40.Can a triangle have sides of 12 cm, 18 cm and 5 cm? (a) No (b) Yes

Answer key

  1. 90
  2. 29
  3. 25
  4. 50
  5. 96
  6. 117
  7. No
  8. 90
  9. 44
  10. 47
  11. No
  12. 17
  13. 101
  14. 70
  15. 100
  16. 98
  17. Yes
  18. No
  19. 73
  20. 56
  21. 90
  22. No
  23. 40
  24. 25
  25. 83
  26. 52
  27. 18
  28. 24
  29. 49
  30. 120
  31. 5
  32. 58
  33. 31
  34. No
  35. 60
  36. 33
  37. 12
  38. 23
  39. 77
  40. No

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