← 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 440 · 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 1 : 2 : 6. What is the biggest angle (in degrees)?
  2. 2.The two interior opposite angles of a triangle are 26° and 52°. What is the exterior angle (in degrees)?
  3. 3.An exterior angle of a triangle is 61°. One of its two interior opposite angles is 36°. What is the other one (in degrees)?
  4. 4.The angles of a triangle are in the ratio 2 : 2 : 5. What is the biggest angle (in degrees)?
  5. 5.The angles of a triangle are in the ratio 1 : 2 : 3. What is the smallest angle (in degrees)?
  6. 6.In triangle ABC, angle A = 94° and angle B = 59°. What is angle C (in degrees)?
  7. 7.Can a triangle have sides of 2 cm, 2 cm and 3 cm? (a) No (b) Yes
  8. 8.In triangle ABC, angle A = 38° and angle B = 101°. What is angle C (in degrees)?
  9. 9.An exterior angle of a triangle is 104°. One of its two interior opposite angles is 35°. What is the other one (in degrees)?
  10. 10.An exterior angle of a triangle is 134°. One of its two interior opposite angles is 61°. What is the other one (in degrees)?
  11. 11.An exterior angle of a triangle is 81°. One of its two interior opposite angles is 26°. What is the other one (in degrees)?
  12. 12.In triangle ABC, angle A = 63° and angle B = 56°. What is angle C (in degrees)?
  13. 13.Can a triangle have sides of 11 cm, 23 cm and 9 cm? (a) No (b) Yes
  14. 14.The angles of a triangle are in the ratio 2 : 2 : 5. What is the smallest angle (in degrees)?
  15. 15.In triangle ABC, angle A = 68° and angle B = 68°. What is angle C (in degrees)?
  16. 16.The longest side of a right-angled triangle is 25 cm and one of the other sides is 24 cm. How long is the third side (in cm)?
  17. 17.In triangle ABC, angle A = 72° and angle B = 85°. What is angle C (in degrees)?
  18. 18.In triangle ABC, angle A = 76° and angle B = 35°. What is angle C (in degrees)?
  19. 19.The two shorter sides of a right-angled triangle are 7 cm and 24 cm. How long is the longest side (in cm)?
  20. 20.The two interior opposite angles of a triangle are 56° and 22°. What is the exterior angle (in degrees)?
  21. 21.In an isosceles triangle, the two equal angles are 55° each. What is the third angle (in degrees)?
  22. 22.In triangle ABC, angle A = 47° and angle B = 27°. 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 triangle ABC, angle A = 33° and angle B = 34°. What is angle C (in degrees)?
  25. 25.The two interior opposite angles of a triangle are 32° and 65°. What is the exterior angle (in degrees)?
  26. 26.In a right-angled triangle, one of the other two angles is 30°. What is the third angle (in degrees)?
  27. 27.An exterior angle of a triangle is 54°. One of its two interior opposite angles is 21°. What is the other one (in degrees)?
  28. 28.The two shorter sides of a right-angled triangle are 15 cm and 8 cm. How long is the longest side (in cm)?
  29. 29.In triangle ABC, angle A = 40° and angle B = 96°. What is angle C (in degrees)?
  30. 30.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)?
  31. 31.In a right-angled triangle, one of the other two angles is 44°. What is the third angle (in degrees)?
  32. 32.In triangle ABC, angle A = 32° and angle B = 22°. What is angle C (in degrees)?
  33. 33.In an isosceles triangle, the angle between the two equal sides is 150°. What is each of the other two angles (in degrees)?
  34. 34.Can a triangle have sides of 19 cm, 9 cm and 11 cm? (a) No (b) Yes
  35. 35.The longest side of a right-angled triangle is 30 cm and one of the other sides is 24 cm. How long is the third side (in cm)?
  36. 36.The angles of a triangle are in the ratio 2 : 3 : 5. What is the smallest angle (in degrees)?
  37. 37.An exterior angle of a triangle is 94°. One of its two interior opposite angles is 30°. What is the other one (in degrees)?
  38. 38.In an isosceles triangle, the two equal angles are 65° each. What is the third angle (in degrees)?
  39. 39.Can a triangle have sides of 6 cm, 5 cm and 2 cm? (a) Yes (b) No
  40. 40.In triangle ABC, angle A = 37° and angle B = 103°. What is angle C (in degrees)?

Answer key

  1. 120
  2. 78
  3. 25
  4. 100
  5. 30
  6. 27
  7. Yes
  8. 41
  9. 69
  10. 73
  11. 55
  12. 61
  13. No
  14. 40
  15. 44
  16. 7
  17. 23
  18. 69
  19. 25
  20. 78
  21. 70
  22. 106
  23. 90
  24. 113
  25. 97
  26. 60
  27. 33
  28. 17
  29. 44
  30. 36
  31. 46
  32. 126
  33. 15
  34. Yes
  35. 18
  36. 36
  37. 64
  38. 50
  39. Yes
  40. 40

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