← 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 294 · 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 a right-angled triangle, one of the other two angles is 59°. What is the third angle (in degrees)?
  2. 2.Can a triangle have sides of 16 cm, 4 cm and 10 cm? (a) Yes (b) No
  3. 3.The angles of a triangle are in the ratio 3 : 4 : 5. What is the biggest angle (in degrees)?
  4. 4.The two interior opposite angles of a triangle are 42° and 28°. What is the exterior angle (in degrees)?
  5. 5.The angles of a triangle are in the ratio 5 : 6 : 7. What is the smallest angle (in degrees)?
  6. 6.The two interior opposite angles of a triangle are 62° and 46°. What is the exterior angle (in degrees)?
  7. 7.The two interior opposite angles of a triangle are 26° and 53°. What is the exterior 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 an isosceles triangle, the angle between the two equal sides is 132°. What is each of the other two angles (in degrees)?
  10. 10.An exterior angle of a triangle is 61°. One of its two interior opposite angles is 41°. What is the other one (in degrees)?
  11. 11.Can a triangle have sides of 2 cm, 7 cm and 7 cm? (a) Yes (b) No
  12. 12.The longest side of a right-angled triangle is 20 cm and one of the other sides is 16 cm. How long is the third side (in cm)?
  13. 13.Can a triangle have sides of 10 cm, 11 cm and 24 cm? (a) Yes (b) No
  14. 14.In a right-angled triangle, one of the other two angles is 16°. What is the third angle (in degrees)?
  15. 15.The angles of a triangle are in the ratio 1 : 3 : 5. What is the smallest angle (in degrees)?
  16. 16.Can a triangle have sides of 9 cm, 8 cm and 14 cm? (a) Yes (b) No
  17. 17.In a right-angled triangle, one of the other two angles is 47°. What is the third angle (in degrees)?
  18. 18.Can a triangle have sides of 21 cm, 9 cm and 12 cm? (a) Yes (b) No
  19. 19.In triangle ABC, angle A = 57° and angle B = 53°. What is angle C (in degrees)?
  20. 20.In a right-angled triangle, one of the other two angles is 49°. What is the third angle (in degrees)?
  21. 21.An exterior angle of a triangle is 74°. One of its two interior opposite angles is 43°. What is the other one (in degrees)?
  22. 22.In a right-angled triangle, one of the other two angles is 76°. What is the third angle (in degrees)?
  23. 23.In triangle ABC, angle A = 30° and angle B = 22°. What is angle C (in degrees)?
  24. 24.An exterior angle of a triangle is 100°. One of its two interior opposite angles is 53°. What is the other one (in degrees)?
  25. 25.The two interior opposite angles of a triangle are 28° and 52°. What is the exterior angle (in degrees)?
  26. 26.The angles of a triangle are in the ratio 4 : 5 : 6. What is the biggest angle (in degrees)?
  27. 27.In a right-angled triangle, one of the other two angles is 60°. What is the third angle (in degrees)?
  28. 28.In triangle ABC, angle A = 40° and angle B = 30°. What is angle C (in degrees)?
  29. 29.Can a triangle have sides of 14 cm, 8 cm and 8 cm? (a) No (b) Yes
  30. 30.An exterior angle of a triangle is 121°. One of its two interior opposite angles is 69°. What is the other one (in degrees)?
  31. 31.The two shorter sides of a right-angled triangle are 24 cm and 10 cm. How long is the longest side (in cm)?
  32. 32.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)?
  33. 33.An exterior angle of a triangle is 109°. One of its two interior opposite angles is 60°. What is the other one (in degrees)?
  34. 34.In triangle ABC, angle A = 30° and angle B = 80°. What is angle C (in degrees)?
  35. 35.The two shorter sides of a right-angled triangle are 3 cm and 4 cm. How long is the longest side (in cm)?
  36. 36.The two interior opposite angles of a triangle are 69° and 80°. What is the exterior angle (in degrees)?
  37. 37.Can a triangle have sides of 6 cm, 7 cm and 16 cm? (a) Yes (b) No
  38. 38.In a right-angled triangle, one of the other two angles is 58°. What is the third angle (in degrees)?
  39. 39.In a right-angled triangle, one of the other two angles is 39°. What is the third angle (in degrees)?
  40. 40.Can a triangle have sides of 6 cm, 4 cm and 12 cm? (a) Yes (b) No

Answer key

  1. 31
  2. No
  3. 75
  4. 70
  5. 50
  6. 108
  7. 79
  8. 90
  9. 24
  10. 20
  11. Yes
  12. 12
  13. No
  14. 74
  15. 20
  16. Yes
  17. 43
  18. No
  19. 70
  20. 41
  21. 31
  22. 14
  23. 128
  24. 47
  25. 80
  26. 72
  27. 30
  28. 110
  29. Yes
  30. 52
  31. 26
  32. 7
  33. 49
  34. 70
  35. 5
  36. 149
  37. No
  38. 32
  39. 51
  40. No

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