← 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 120 · 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 77°. One of its two interior opposite angles is 26°. What is the other one (in degrees)?
  2. 2.Can a triangle have sides of 11 cm, 20 cm and 9 cm? (a) Yes (b) No
  3. 3.In an isosceles triangle, the angle between the two equal sides is 84°. What is each of the other two angles (in degrees)?
  4. 4.In an isosceles triangle, the two equal angles are 44° each. What is the third angle (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 an isosceles triangle, the angle between the two equal sides is 40°. What is each of the other two angles (in degrees)?
  7. 7.In an isosceles triangle, the two equal angles are 43° each. What is the third angle (in degrees)?
  8. 8.In a right-angled triangle, one of the other two angles is 71°. What is the third angle (in degrees)?
  9. 9.The two shorter sides of a right-angled triangle are 24 cm and 7 cm. How long is the longest side (in cm)?
  10. 10.The two interior opposite angles of a triangle are 73° and 30°. What is the exterior angle (in degrees)?
  11. 11.Can a triangle have sides of 8 cm, 4 cm and 9 cm? (a) Yes (b) No
  12. 12.In a right-angled triangle, one of the other two angles is 34°. What is the third angle (in degrees)?
  13. 13.In triangle ABC, angle A = 30° and angle B = 105°. What is angle C (in degrees)?
  14. 14.Can a triangle have sides of 12 cm, 4 cm and 13 cm? (a) No (b) Yes
  15. 15.An exterior angle of a triangle is 147°. One of its two interior opposite angles is 74°. What is the other one (in degrees)?
  16. 16.The angles of a triangle are in the ratio 3 : 4 : 5. What is the smallest angle (in degrees)?
  17. 17.The two shorter sides of a right-angled triangle are 7 cm and 24 cm. How long is the longest side (in cm)?
  18. 18.In an isosceles triangle, the angle between the two equal sides is 158°. What is each of the other two angles (in degrees)?
  19. 19.In an isosceles triangle, the angle between the two equal sides is 100°. What is each of the other two angles (in degrees)?
  20. 20.Can a triangle have sides of 7 cm, 7 cm and 15 cm? (a) No (b) Yes
  21. 21.In a right-angled triangle, one of the other two angles is 28°. What is the third angle (in degrees)?
  22. 22.The angles of a triangle are in the ratio 2 : 3 : 4. What is the biggest angle (in degrees)?
  23. 23.In an isosceles triangle, the angle between the two equal sides is 60°. What is each of the other two angles (in degrees)?
  24. 24.The angles of a triangle are in the ratio 2 : 3 : 5. What is the biggest angle (in degrees)?
  25. 25.In triangle ABC, angle A = 97° and angle B = 26°. What is angle C (in degrees)?
  26. 26.In triangle ABC, angle A = 74° and angle B = 73°. What is angle C (in degrees)?
  27. 27.In a right-angled triangle, one of the other two angles is 77°. What is the third angle (in degrees)?
  28. 28.Can a triangle have sides of 4 cm, 15 cm and 8 cm? (a) No (b) Yes
  29. 29.The two shorter sides of a right-angled triangle are 12 cm and 16 cm. How long is the longest side (in cm)?
  30. 30.In a right-angled triangle, one of the other two angles is 79°. What is the third angle (in degrees)?
  31. 31.An exterior angle of a triangle is 48°. One of its two interior opposite angles is 23°. What is the other one (in degrees)?
  32. 32.The angles of a triangle are in the ratio 1 : 1 : 2. What is the smallest angle (in degrees)?
  33. 33.Can a triangle have sides of 6 cm, 11 cm and 21 cm? (a) Yes (b) No
  34. 34.In triangle ABC, angle A = 44° and angle B = 50°. What is angle C (in degrees)?
  35. 35.An exterior angle of a triangle is 68°. One of its two interior opposite angles is 37°. What is the other one (in degrees)?
  36. 36.In triangle ABC, angle A = 96° and angle B = 27°. What is angle C (in degrees)?
  37. 37.The longest side of a right-angled triangle is 5 cm and one of the other sides is 3 cm. How long is the third side (in cm)?
  38. 38.Can a triangle have sides of 23 cm, 9 cm and 9 cm? (a) Yes (b) No
  39. 39.In triangle ABC, angle A = 79° and angle B = 49°. What is angle C (in degrees)?
  40. 40.In an isosceles triangle, the angle between the two equal sides is 52°. What is each of the other two angles (in degrees)?

Answer key

  1. 51
  2. No
  3. 48
  4. 92
  5. 112
  6. 70
  7. 94
  8. 19
  9. 25
  10. 103
  11. Yes
  12. 56
  13. 45
  14. Yes
  15. 73
  16. 45
  17. 25
  18. 11
  19. 40
  20. No
  21. 62
  22. 80
  23. 60
  24. 90
  25. 57
  26. 33
  27. 13
  28. No
  29. 20
  30. 11
  31. 25
  32. 45
  33. No
  34. 86
  35. 31
  36. 57
  37. 4
  38. No
  39. 52
  40. 64

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