← 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 90 · 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 = 27° and angle B = 74°. What is angle C (in degrees)?
  2. 2.The two shorter sides of a right-angled triangle are 8 cm and 15 cm. How long is the longest side (in cm)?
  3. 3.The angles of a triangle are in the ratio 2 : 2 : 5. What is the biggest angle (in degrees)?
  4. 4.In triangle ABC, angle A = 40° and angle B = 70°. What is angle C (in degrees)?
  5. 5.Can a triangle have sides of 8 cm, 19 cm and 10 cm? (a) No (b) Yes
  6. 6.In triangle ABC, angle A = 73° and angle B = 76°. What is angle C (in degrees)?
  7. 7.The two interior opposite angles of a triangle are 76° and 34°. What is the exterior angle (in degrees)?
  8. 8.In a right-angled triangle, one of the other two angles is 47°. What is the third angle (in degrees)?
  9. 9.Can a triangle have sides of 14 cm, 10 cm and 10 cm? (a) Yes (b) No
  10. 10.In a right-angled triangle, one of the other two angles is 66°. What is the third angle (in degrees)?
  11. 11.The angles of a triangle are in the ratio 3 : 4 : 5. What is the smallest angle (in degrees)?
  12. 12.Can a triangle have sides of 8 cm, 7 cm and 2 cm? (a) No (b) Yes
  13. 13.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)?
  14. 14.In an isosceles triangle, the two equal angles are 69° each. What is the third angle (in degrees)?
  15. 15.Can a triangle have sides of 6 cm, 6 cm and 8 cm? (a) Yes (b) No
  16. 16.The angles of a triangle are in the ratio 3 : 4 : 5. What is the biggest angle (in degrees)?
  17. 17.The angles of a triangle are in the ratio 1 : 2 : 6. What is the smallest angle (in degrees)?
  18. 18.Can a triangle have sides of 3 cm, 5 cm and 6 cm? (a) No (b) Yes
  19. 19.The two interior opposite angles of a triangle are 34° and 37°. What is the exterior angle (in degrees)?
  20. 20.In an isosceles triangle, the angle between the two equal sides is 112°. What is each of the other two angles (in degrees)?
  21. 21.An exterior angle of a triangle is 113°. One of its two interior opposite angles is 67°. What is the other one (in degrees)?
  22. 22.In a right-angled triangle, one of the other two angles is 63°. What is the third angle (in degrees)?
  23. 23.In a right-angled triangle, one of the other two angles is 18°. What is the third angle (in degrees)?
  24. 24.The two shorter sides of a right-angled triangle are 10 cm and 24 cm. How long is the longest side (in cm)?
  25. 25.Can a triangle have sides of 8 cm, 1 cm and 8 cm? (a) No (b) Yes
  26. 26.Can a triangle have sides of 6 cm, 13 cm and 7 cm? (a) Yes (b) No
  27. 27.The angles of a triangle are in the ratio 3 : 3 : 4. What is the smallest angle (in degrees)?
  28. 28.The angles of a triangle are in the ratio 1 : 2 : 3. What is the biggest angle (in degrees)?
  29. 29.In triangle ABC, angle A = 87° and angle B = 43°. What is angle C (in degrees)?
  30. 30.In a right-angled triangle, one of the other two angles is 10°. What is the third angle (in degrees)?
  31. 31.In triangle ABC, angle A = 88° and angle B = 22°. What is angle C (in degrees)?
  32. 32.The angles of a triangle are in the ratio 5 : 6 : 7. What is the biggest angle (in degrees)?
  33. 33.The angles of a triangle are in the ratio 2 : 7 : 9. What is the smallest angle (in degrees)?
  34. 34.In an isosceles triangle, the two equal angles are 63° each. What is the third angle (in degrees)?
  35. 35.In triangle ABC, angle A = 85° and angle B = 48°. What is angle C (in degrees)?
  36. 36.The two shorter sides of a right-angled triangle are 24 cm and 7 cm. How long is the longest side (in cm)?
  37. 37.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)?
  38. 38.In an isosceles triangle, the angle between the two equal sides is 160°. What is each of the other two angles (in degrees)?
  39. 39.In a right-angled triangle, one of the other two angles is 59°. What is the third angle (in degrees)?
  40. 40.In an isosceles triangle, the angle between the two equal sides is 28°. What is each of the other two angles (in degrees)?

Answer key

  1. 79
  2. 17
  3. 100
  4. 70
  5. No
  6. 31
  7. 110
  8. 43
  9. Yes
  10. 24
  11. 45
  12. Yes
  13. 7
  14. 42
  15. Yes
  16. 75
  17. 20
  18. Yes
  19. 71
  20. 34
  21. 46
  22. 27
  23. 72
  24. 26
  25. Yes
  26. No
  27. 54
  28. 90
  29. 50
  30. 80
  31. 70
  32. 70
  33. 20
  34. 54
  35. 47
  36. 25
  37. 36
  38. 10
  39. 31
  40. 76

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