← 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 719 · 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.Can a triangle have sides of 7 cm, 4 cm and 5 cm? (a) No (b) Yes
  2. 2.The angles of a triangle are in the ratio 5 : 6 : 7. What is the smallest angle (in degrees)?
  3. 3.Can a triangle have sides of 15 cm, 10 cm and 11 cm? (a) Yes (b) No
  4. 4.Can a triangle have sides of 10 cm, 20 cm and 10 cm? (a) No (b) Yes
  5. 5.In triangle ABC, angle A = 23° and angle B = 93°. What is angle C (in degrees)?
  6. 6.The two shorter sides of a right-angled triangle are 10 cm and 24 cm. How long is the longest side (in cm)?
  7. 7.In a right-angled triangle, one of the other two angles is 30°. What is the third angle (in degrees)?
  8. 8.The two interior opposite angles of a triangle are 24° and 26°. What is the exterior angle (in degrees)?
  9. 9.An exterior angle of a triangle is 114°. One of its two interior opposite angles is 36°. What is the other one (in degrees)?
  10. 10.Can a triangle have sides of 10 cm, 20 cm and 9 cm? (a) Yes (b) No
  11. 11.An exterior angle of a triangle is 112°. One of its two interior opposite angles is 44°. What is the other one (in degrees)?
  12. 12.In triangle ABC, angle A = 44° and angle B = 38°. What is angle C (in degrees)?
  13. 13.The two interior opposite angles of a triangle are 66° and 76°. What is the exterior angle (in degrees)?
  14. 14.Can a triangle have sides of 15 cm, 8 cm and 8 cm? (a) Yes (b) No
  15. 15.An exterior angle of a triangle is 86°. One of its two interior opposite angles is 27°. What is the other one (in degrees)?
  16. 16.In a right-angled triangle, one of the other two angles is 29°. What is the third angle (in degrees)?
  17. 17.The angles of a triangle are in the ratio 1 : 2 : 3. What is the smallest angle (in degrees)?
  18. 18.An exterior angle of a triangle is 67°. One of its two interior opposite angles is 23°. What is the other one (in degrees)?
  19. 19.The angles of a triangle are in the ratio 4 : 5 : 6. What is the biggest angle (in degrees)?
  20. 20.The longest side of a right-angled triangle is 39 cm and one of the other sides is 15 cm. How long is the third side (in cm)?
  21. 21.Can a triangle have sides of 11 cm, 8 cm and 4 cm? (a) Yes (b) No
  22. 22.In an isosceles triangle, the two equal angles are 49° each. What is the third angle (in degrees)?
  23. 23.An exterior angle of a triangle is 73°. One of its two interior opposite angles is 30°. What is the other one (in degrees)?
  24. 24.In a right-angled triangle, one of the other two angles is 67°. What is the third angle (in degrees)?
  25. 25.An exterior angle of a triangle is 53°. One of its two interior opposite angles is 33°. What is the other one (in degrees)?
  26. 26.Can a triangle have sides of 6 cm, 4 cm and 8 cm? (a) No (b) Yes
  27. 27.The two interior opposite angles of a triangle are 65° and 31°. What is the exterior angle (in degrees)?
  28. 28.In triangle ABC, angle A = 37° and angle B = 45°. What is angle C (in degrees)?
  29. 29.The angles of a triangle are in the ratio 1 : 2 : 6. What is the biggest angle (in degrees)?
  30. 30.In triangle ABC, angle A = 53° and angle B = 66°. What is angle C (in degrees)?
  31. 31.In a right-angled triangle, one of the other two angles is 59°. What is the third angle (in degrees)?
  32. 32.In triangle ABC, angle A = 40° and angle B = 53°. What is angle C (in degrees)?
  33. 33.An exterior angle of a triangle is 96°. One of its two interior opposite angles is 39°. What is the other one (in degrees)?
  34. 34.In triangle ABC, angle A = 90° and angle B = 58°. What is angle C (in degrees)?
  35. 35.The two shorter sides of a right-angled triangle are 12 cm and 16 cm. How long is the longest side (in cm)?
  36. 36.Can a triangle have sides of 7 cm, 3 cm and 13 cm? (a) No (b) Yes
  37. 37.In a right-angled triangle, one of the other two angles is 50°. What is the third angle (in degrees)?
  38. 38.In a right-angled triangle, one of the other two angles is 18°. What is the third angle (in degrees)?
  39. 39.In triangle ABC, angle A = 76° and angle B = 39°. What is angle C (in degrees)?
  40. 40.In an isosceles triangle, the two equal angles are 34° each. What is the third angle (in degrees)?

Answer key

  1. Yes
  2. 50
  3. Yes
  4. No
  5. 64
  6. 26
  7. 60
  8. 50
  9. 78
  10. No
  11. 68
  12. 98
  13. 142
  14. Yes
  15. 59
  16. 61
  17. 30
  18. 44
  19. 72
  20. 36
  21. Yes
  22. 82
  23. 43
  24. 23
  25. 20
  26. Yes
  27. 96
  28. 98
  29. 120
  30. 61
  31. 31
  32. 87
  33. 57
  34. 32
  35. 20
  36. No
  37. 40
  38. 72
  39. 65
  40. 112

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