← 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 524 · 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.The two shorter sides of a right-angled triangle are 20 cm and 15 cm. How long is the longest side (in cm)?
  2. 2.In a right-angled triangle, one of the other two angles is 40°. What is the third angle (in degrees)?
  3. 3.In an isosceles triangle, the angle between the two equal sides is 148°. What is each of the other two angles (in degrees)?
  4. 4.Can a triangle have sides of 8 cm, 6 cm and 11 cm? (a) Yes (b) No
  5. 5.In an isosceles triangle, the angle between the two equal sides is 52°. What is each of the other two angles (in degrees)?
  6. 6.In triangle ABC, angle A = 56° and angle B = 98°. What is angle C (in degrees)?
  7. 7.The angles of a triangle are in the ratio 1 : 2 : 3. What is the smallest angle (in degrees)?
  8. 8.The angles of a triangle are in the ratio 2 : 3 : 5. What is the biggest angle (in degrees)?
  9. 9.In triangle ABC, angle A = 92° and angle B = 26°. What is angle C (in degrees)?
  10. 10.In an isosceles triangle, the angle between the two equal sides is 142°. What is each of the other two angles (in degrees)?
  11. 11.The two shorter sides of a right-angled triangle are 10 cm and 24 cm. How long is the longest side (in cm)?
  12. 12.An exterior angle of a triangle is 60°. One of its two interior opposite angles is 27°. What is the other one (in degrees)?
  13. 13.In an isosceles triangle, the two equal angles are 45° each. What is the third angle (in degrees)?
  14. 14.In an isosceles triangle, the angle between the two equal sides is 120°. What is each of the other two angles (in degrees)?
  15. 15.The angles of a triangle are in the ratio 1 : 2 : 3. What is the biggest angle (in degrees)?
  16. 16.Can a triangle have sides of 8 cm, 15 cm and 3 cm? (a) Yes (b) No
  17. 17.Can a triangle have sides of 11 cm, 3 cm and 5 cm? (a) Yes (b) No
  18. 18.The two shorter sides of a right-angled triangle are 12 cm and 5 cm. How long is the longest side (in cm)?
  19. 19.The angles of a triangle are in the ratio 3 : 5 : 7. What is the biggest angle (in degrees)?
  20. 20.In an isosceles triangle, the two equal angles are 64° each. What is the third angle (in degrees)?
  21. 21.In an isosceles triangle, the two equal angles are 25° each. What is the third angle (in degrees)?
  22. 22.The two interior opposite angles of a triangle are 41° and 59°. What is the exterior angle (in degrees)?
  23. 23.The angles of a triangle are in the ratio 3 : 3 : 4. What is the biggest angle (in degrees)?
  24. 24.The angles of a triangle are in the ratio 2 : 7 : 9. What is the biggest angle (in degrees)?
  25. 25.An exterior angle of a triangle is 78°. One of its two interior opposite angles is 21°. What is the other one (in degrees)?
  26. 26.Can a triangle have sides of 2 cm, 12 cm and 8 cm? (a) Yes (b) No
  27. 27.In a right-angled triangle, one of the other two angles is 41°. What is the third angle (in degrees)?
  28. 28.An exterior angle of a triangle is 108°. One of its two interior opposite angles is 35°. What is the other one (in degrees)?
  29. 29.In an isosceles triangle, the angle between the two equal sides is 138°. What is each of the other two angles (in degrees)?
  30. 30.In an isosceles triangle, the angle between the two equal sides is 28°. What is each of the other two angles (in degrees)?
  31. 31.The two shorter sides of a right-angled triangle are 15 cm and 8 cm. How long is the longest side (in cm)?
  32. 32.Can a triangle have sides of 3 cm, 9 cm and 9 cm? (a) No (b) Yes
  33. 33.In an isosceles triangle, the angle between the two equal sides is 36°. What is each of the other two angles (in degrees)?
  34. 34.The two shorter sides of a right-angled triangle are 24 cm and 7 cm. How long is the longest side (in cm)?
  35. 35.In a right-angled triangle, one of the other two angles is 58°. What is the third angle (in degrees)?
  36. 36.In triangle ABC, angle A = 48° and angle B = 32°. What is angle C (in degrees)?
  37. 37.The two shorter sides of a right-angled triangle are 24 cm and 10 cm. How long is the longest side (in cm)?
  38. 38.In a right-angled triangle, one of the other two angles is 23°. What is the third angle (in degrees)?
  39. 39.The angles of a triangle are in the ratio 2 : 3 : 5. What is the smallest angle (in degrees)?
  40. 40.In a right-angled triangle, one of the other two angles is 12°. What is the third angle (in degrees)?

Answer key

  1. 25
  2. 50
  3. 16
  4. Yes
  5. 64
  6. 26
  7. 30
  8. 90
  9. 62
  10. 19
  11. 26
  12. 33
  13. 90
  14. 30
  15. 90
  16. No
  17. No
  18. 13
  19. 84
  20. 52
  21. 130
  22. 100
  23. 72
  24. 90
  25. 57
  26. No
  27. 49
  28. 73
  29. 21
  30. 76
  31. 17
  32. Yes
  33. 72
  34. 25
  35. 32
  36. 100
  37. 26
  38. 67
  39. 36
  40. 78

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