← 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 426 · 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 87°. One of its two interior opposite angles is 25°. What is the other one (in degrees)?
  2. 2.In an isosceles triangle, the angle between the two equal sides is 144°. What is each of the other two angles (in degrees)?
  3. 3.The two interior opposite angles of a triangle are 60° and 56°. What is the exterior angle (in degrees)?
  4. 4.In a right-angled triangle, one of the other two angles is 67°. What is the third angle (in degrees)?
  5. 5.In triangle ABC, angle A = 54° and angle B = 59°. What is angle C (in degrees)?
  6. 6.Can a triangle have sides of 4 cm, 13 cm and 6 cm? (a) Yes (b) No
  7. 7.An exterior angle of a triangle is 109°. One of its two interior opposite angles is 59°. What is the other one (in degrees)?
  8. 8.In a right-angled triangle, one of the other two angles is 12°. What is the third angle (in degrees)?
  9. 9.In a right-angled triangle, one of the other two angles is 41°. What is the third angle (in degrees)?
  10. 10.Can a triangle have sides of 15 cm, 4 cm and 7 cm? (a) Yes (b) No
  11. 11.The two shorter sides of a right-angled triangle are 7 cm and 24 cm. How long is the longest side (in cm)?
  12. 12.The angles of a triangle are in the ratio 2 : 7 : 9. What is the biggest angle (in degrees)?
  13. 13.The two shorter sides of a right-angled triangle are 8 cm and 15 cm. How long is the longest side (in cm)?
  14. 14.In an isosceles triangle, the angle between the two equal sides is 114°. What is each of the other two angles (in degrees)?
  15. 15.The two interior opposite angles of a triangle are 35° and 62°. What is the exterior angle (in degrees)?
  16. 16.Can a triangle have sides of 4 cm, 7 cm and 3 cm? (a) Yes (b) No
  17. 17.In triangle ABC, angle A = 67° and angle B = 35°. What is angle C (in degrees)?
  18. 18.The two shorter sides of a right-angled triangle are 15 cm and 8 cm. How long is the longest side (in cm)?
  19. 19.The two interior opposite angles of a triangle are 38° and 43°. What is the exterior angle (in degrees)?
  20. 20.In triangle ABC, angle A = 90° and angle B = 67°. What is angle C (in degrees)?
  21. 21.The two interior opposite angles of a triangle are 43° and 62°. What is the exterior angle (in degrees)?
  22. 22.In triangle ABC, angle A = 84° and angle B = 62°. What is angle C (in degrees)?
  23. 23.In an isosceles triangle, the angle between the two equal sides is 132°. What is each of the other two angles (in degrees)?
  24. 24.In triangle ABC, angle A = 45° and angle B = 53°. What is angle C (in degrees)?
  25. 25.The two shorter sides of a right-angled triangle are 4 cm and 3 cm. How long is the longest side (in cm)?
  26. 26.In triangle ABC, angle A = 54° and angle B = 80°. What is angle C (in degrees)?
  27. 27.In an isosceles triangle, the angle between the two equal sides is 122°. What is each of the other two angles (in degrees)?
  28. 28.In triangle ABC, angle A = 84° and angle B = 33°. What is angle C (in degrees)?
  29. 29.Can a triangle have sides of 9 cm, 5 cm and 5 cm? (a) No (b) Yes
  30. 30.In a right-angled triangle, one of the other two angles is 23°. What is the third angle (in degrees)?
  31. 31.In a right-angled triangle, one of the other two angles is 49°. What is the third angle (in degrees)?
  32. 32.The two interior opposite angles of a triangle are 74° and 45°. What is the exterior angle (in degrees)?
  33. 33.An exterior angle of a triangle is 127°. One of its two interior opposite angles is 67°. What is the other one (in degrees)?
  34. 34.In triangle ABC, angle A = 65° and angle B = 83°. What is angle C (in degrees)?
  35. 35.In a right-angled triangle, one of the other two angles is 56°. What is the third angle (in degrees)?
  36. 36.An exterior angle of a triangle is 102°. One of its two interior opposite angles is 30°. What is the other one (in degrees)?
  37. 37.In an isosceles triangle, the angle between the two equal sides is 86°. What is each of the other two angles (in degrees)?
  38. 38.In a right-angled triangle, one of the other two angles is 65°. What is the third angle (in degrees)?
  39. 39.Can a triangle have sides of 10 cm, 21 cm and 10 cm? (a) Yes (b) No
  40. 40.Can a triangle have sides of 12 cm, 3 cm and 13 cm? (a) No (b) Yes

Answer key

  1. 62
  2. 18
  3. 116
  4. 23
  5. 67
  6. No
  7. 50
  8. 78
  9. 49
  10. No
  11. 25
  12. 90
  13. 17
  14. 33
  15. 97
  16. No
  17. 78
  18. 17
  19. 81
  20. 23
  21. 105
  22. 34
  23. 24
  24. 82
  25. 5
  26. 46
  27. 29
  28. 63
  29. Yes
  30. 67
  31. 41
  32. 119
  33. 60
  34. 32
  35. 34
  36. 72
  37. 47
  38. 25
  39. No
  40. Yes

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