← 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 884 · 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.In triangle ABC, angle A = 79° and angle B = 53°. What is angle C (in degrees)?
  2. 2.In triangle ABC, angle A = 79° and angle B = 32°. What is angle C (in degrees)?
  3. 3.In triangle ABC, angle A = 22° and angle B = 28°. What is angle C (in degrees)?
  4. 4.An exterior angle of a triangle is 74°. One of its two interior opposite angles is 53°. What is the other one (in degrees)?
  5. 5.The angles of a triangle are in the ratio 3 : 5 : 7. What is the biggest angle (in degrees)?
  6. 6.In an isosceles triangle, the two equal angles are 33° each. What is the third angle (in degrees)?
  7. 7.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)?
  8. 8.The angles of a triangle are in the ratio 1 : 4 : 5. What is the smallest angle (in degrees)?
  9. 9.In triangle ABC, angle A = 72° and angle B = 20°. What is angle C (in degrees)?
  10. 10.The longest side of a right-angled triangle is 15 cm and one of the other sides is 12 cm. How long is the third side (in cm)?
  11. 11.An exterior angle of a triangle is 65°. One of its two interior opposite angles is 38°. What is the other one (in degrees)?
  12. 12.The two interior opposite angles of a triangle are 52° and 78°. What is the exterior angle (in degrees)?
  13. 13.In an isosceles triangle, the two equal angles are 84° each. What is the third angle (in degrees)?
  14. 14.In triangle ABC, angle A = 92° and angle B = 50°. What is angle C (in degrees)?
  15. 15.An exterior angle of a triangle is 86°. One of its two interior opposite angles is 37°. What is the other one (in degrees)?
  16. 16.Can a triangle have sides of 17 cm, 6 cm and 6 cm? (a) Yes (b) No
  17. 17.In an isosceles triangle, the two equal angles are 81° each. What is the third angle (in degrees)?
  18. 18.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)?
  19. 19.Can a triangle have sides of 13 cm, 9 cm and 8 cm? (a) Yes (b) No
  20. 20.In triangle ABC, angle A = 33° and angle B = 33°. What is angle C (in degrees)?
  21. 21.In triangle ABC, angle A = 46° and angle B = 73°. What is angle C (in degrees)?
  22. 22.The two interior opposite angles of a triangle are 69° and 65°. What is the exterior angle (in degrees)?
  23. 23.In an isosceles triangle, the two equal angles are 66° each. What is the third angle (in degrees)?
  24. 24.In an isosceles triangle, the angle between the two equal sides is 84°. What is each of the other two angles (in degrees)?
  25. 25.The angles of a triangle are in the ratio 1 : 1 : 2. What is the biggest angle (in degrees)?
  26. 26.In triangle ABC, angle A = 69° and angle B = 39°. What is angle C (in degrees)?
  27. 27.The longest side of a right-angled triangle is 17 cm and one of the other sides is 15 cm. How long is the third side (in cm)?
  28. 28.Can a triangle have sides of 8 cm, 6 cm and 6 cm? (a) Yes (b) No
  29. 29.In a right-angled triangle, one of the other two angles is 69°. What is the third angle (in degrees)?
  30. 30.In an isosceles triangle, the two equal angles are 77° each. What is the third angle (in degrees)?
  31. 31.Can a triangle have sides of 10 cm, 10 cm and 2 cm? (a) No (b) Yes
  32. 32.The two shorter sides of a right-angled triangle are 15 cm and 8 cm. How long is the longest side (in cm)?
  33. 33.An exterior angle of a triangle is 115°. One of its two interior opposite angles is 76°. What is the other one (in degrees)?
  34. 34.In a right-angled triangle, one of the other two angles is 72°. What is the third angle (in degrees)?
  35. 35.The longest side of a right-angled triangle is 10 cm and one of the other sides is 8 cm. How long is the third side (in cm)?
  36. 36.Can a triangle have sides of 4 cm, 6 cm and 4 cm? (a) No (b) Yes
  37. 37.Can a triangle have sides of 9 cm, 10 cm and 20 cm? (a) No (b) Yes
  38. 38.An exterior angle of a triangle is 100°. One of its two interior opposite angles is 25°. What is the other one (in degrees)?
  39. 39.An exterior angle of a triangle is 136°. One of its two interior opposite angles is 59°. What is the other one (in degrees)?
  40. 40.Can a triangle have sides of 12 cm, 24 cm and 8 cm? (a) No (b) Yes

Answer key

  1. 48
  2. 69
  3. 130
  4. 21
  5. 84
  6. 114
  7. 18
  8. 18
  9. 88
  10. 9
  11. 27
  12. 130
  13. 12
  14. 38
  15. 49
  16. No
  17. 18
  18. 24
  19. Yes
  20. 114
  21. 61
  22. 134
  23. 48
  24. 48
  25. 90
  26. 72
  27. 8
  28. Yes
  29. 21
  30. 26
  31. Yes
  32. 17
  33. 39
  34. 18
  35. 6
  36. Yes
  37. No
  38. 75
  39. 77
  40. No

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