← 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 121 · 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 98°. One of its two interior opposite angles is 56°. What is the other one (in degrees)?
  2. 2.In triangle ABC, angle A = 29° and angle B = 82°. What is angle C (in degrees)?
  3. 3.In triangle ABC, angle A = 21° and angle B = 40°. What is angle C (in degrees)?
  4. 4.In an isosceles triangle, the angle between the two equal sides is 38°. What is each of the other two angles (in degrees)?
  5. 5.In triangle ABC, angle A = 37° and angle B = 81°. What is angle C (in degrees)?
  6. 6.In triangle ABC, angle A = 38° and angle B = 53°. What is angle C (in degrees)?
  7. 7.In a right-angled triangle, one of the other two angles is 27°. What is the third angle (in degrees)?
  8. 8.Can a triangle have sides of 4 cm, 13 cm and 6 cm? (a) No (b) Yes
  9. 9.The angles of a triangle are in the ratio 1 : 2 : 3. What is the smallest angle (in degrees)?
  10. 10.In triangle ABC, angle A = 46° and angle B = 79°. What is angle C (in degrees)?
  11. 11.The two interior opposite angles of a triangle are 55° and 39°. What is the exterior angle (in degrees)?
  12. 12.The angles of a triangle are in the ratio 3 : 4 : 5. What is the smallest angle (in degrees)?
  13. 13.In triangle ABC, angle A = 62° and angle B = 25°. What is angle C (in degrees)?
  14. 14.In triangle ABC, angle A = 62° and angle B = 86°. What is angle C (in degrees)?
  15. 15.The two interior opposite angles of a triangle are 72° and 77°. What is the exterior angle (in degrees)?
  16. 16.The two shorter sides of a right-angled triangle are 15 cm and 36 cm. How long is the longest side (in cm)?
  17. 17.Can a triangle have sides of 10 cm, 6 cm and 18 cm? (a) Yes (b) No
  18. 18.In a right-angled triangle, one of the other two angles is 50°. What is the third angle (in degrees)?
  19. 19.In an isosceles triangle, the two equal angles are 20° each. What is the third angle (in degrees)?
  20. 20.The two shorter sides of a right-angled triangle are 4 cm and 3 cm. How long is the longest side (in cm)?
  21. 21.The two interior opposite angles of a triangle are 44° and 58°. What is the exterior angle (in degrees)?
  22. 22.In triangle ABC, angle A = 27° and angle B = 105°. What is angle C (in degrees)?
  23. 23.In triangle ABC, angle A = 36° and angle B = 97°. What is angle C (in degrees)?
  24. 24.The two shorter sides of a right-angled triangle are 9 cm and 12 cm. How long is the longest side (in cm)?
  25. 25.The two interior opposite angles of a triangle are 80° and 35°. What is the exterior angle (in degrees)?
  26. 26.In triangle ABC, angle A = 24° and angle B = 54°. What is angle C (in degrees)?
  27. 27.The angles of a triangle are in the ratio 1 : 2 : 6. What is the biggest angle (in degrees)?
  28. 28.Can a triangle have sides of 10 cm, 2 cm and 16 cm? (a) No (b) Yes
  29. 29.In triangle ABC, angle A = 53° and angle B = 84°. What is angle C (in degrees)?
  30. 30.In triangle ABC, angle A = 28° and angle B = 23°. What is angle C (in degrees)?
  31. 31.In triangle ABC, angle A = 51° and angle B = 90°. What is angle C (in degrees)?
  32. 32.Can a triangle have sides of 17 cm, 5 cm and 10 cm? (a) No (b) Yes
  33. 33.In an isosceles triangle, the angle between the two equal sides is 44°. What is each of the other two angles (in degrees)?
  34. 34.Can a triangle have sides of 10 cm, 12 cm and 4 cm? (a) Yes (b) No
  35. 35.In a right-angled triangle, one of the other two angles is 60°. What is the third angle (in degrees)?
  36. 36.In a right-angled triangle, one of the other two angles is 24°. What is the third angle (in degrees)?
  37. 37.In triangle ABC, angle A = 61° and angle B = 34°. What is angle C (in degrees)?
  38. 38.The longest side of a right-angled triangle is 13 cm and one of the other sides is 5 cm. How long is the third side (in cm)?
  39. 39.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)?
  40. 40.Can a triangle have sides of 8 cm, 10 cm and 10 cm? (a) No (b) Yes

Answer key

  1. 42
  2. 69
  3. 119
  4. 71
  5. 62
  6. 89
  7. 63
  8. No
  9. 30
  10. 55
  11. 94
  12. 45
  13. 93
  14. 32
  15. 149
  16. 39
  17. No
  18. 40
  19. 140
  20. 5
  21. 102
  22. 48
  23. 47
  24. 15
  25. 115
  26. 102
  27. 120
  28. No
  29. 43
  30. 129
  31. 39
  32. No
  33. 68
  34. Yes
  35. 30
  36. 66
  37. 85
  38. 12
  39. 7
  40. Yes

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