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Class 7 Maths Worksheet: Triangles

Maths worksheets lesson 53: Triangles: angle sum, exterior angle and Pythagoras · Set 494 · 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.

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  1. 1.The two shorter sides of a right-angled triangle are 8 cm and 6 cm. How long is the longest side (in cm)?
  2. 2.In triangle ABC, angle A = 42° and angle B = 25°. What is angle C (in degrees)?
  3. 3.The two shorter sides of a right-angled triangle are 7 cm and 24 cm. How long is the longest side (in cm)?
  4. 4.In triangle ABC, angle A = 25° and angle B = 95°. What is angle C (in degrees)?
  5. 5.Can a triangle have sides of 8 cm, 8 cm and 17 cm? (a) Yes (b) No
  6. 6.In triangle ABC, angle A = 36° and angle B = 107°. What is angle C (in degrees)?
  7. 7.In triangle ABC, angle A = 82° and angle B = 52°. What is angle C (in degrees)?
  8. 8.The angles of a triangle are in the ratio 2 : 3 : 4. What is the smallest angle (in degrees)?
  9. 9.The two shorter sides of a right-angled triangle are 9 cm and 12 cm. How long is the longest side (in cm)?
  10. 10.An exterior angle of a triangle is 92°. One of its two interior opposite angles is 47°. What is the other one (in degrees)?
  11. 11.An exterior angle of a triangle is 114°. One of its two interior opposite angles is 80°. What is the other one (in degrees)?
  12. 12.Can a triangle have sides of 8 cm, 8 cm and 9 cm? (a) No (b) Yes
  13. 13.In triangle ABC, angle A = 24° and angle B = 47°. What is angle C (in degrees)?
  14. 14.In triangle ABC, angle A = 80° and angle B = 32°. What is angle C (in degrees)?
  15. 15.In a right-angled triangle, one of the other two angles is 55°. What is the third angle (in degrees)?
  16. 16.In a right-angled triangle, one of the other two angles is 46°. What is the third angle (in degrees)?
  17. 17.The angles of a triangle are in the ratio 3 : 3 : 4. What is the biggest angle (in degrees)?
  18. 18.Can a triangle have sides of 9 cm, 10 cm and 22 cm? (a) No (b) Yes
  19. 19.In an isosceles triangle, the angle between the two equal sides is 26°. What is each of the other two angles (in degrees)?
  20. 20.The angles of a triangle are in the ratio 2 : 3 : 4. What is the biggest angle (in degrees)?
  21. 21.An exterior angle of a triangle is 93°. One of its two interior opposite angles is 54°. What is the other one (in degrees)?
  22. 22.An exterior angle of a triangle is 50°. One of its two interior opposite angles is 23°. What is the other one (in degrees)?
  23. 23.Can a triangle have sides of 9 cm, 2 cm and 7 cm? (a) Yes (b) No
  24. 24.Can a triangle have sides of 15 cm, 12 cm and 10 cm? (a) No (b) Yes
  25. 25.The two interior opposite angles of a triangle are 31° and 59°. What is the exterior angle (in degrees)?
  26. 26.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)?
  27. 27.In triangle ABC, angle A = 87° and angle B = 55°. What is angle C (in degrees)?
  28. 28.In an isosceles triangle, the angle between the two equal sides is 64°. What is each of the other two angles (in degrees)?
  29. 29.Can a triangle have sides of 10 cm, 8 cm and 8 cm? (a) Yes (b) No
  30. 30.Can a triangle have sides of 21 cm, 5 cm and 12 cm? (a) No (b) Yes
  31. 31.The angles of a triangle are in the ratio 1 : 3 : 5. What is the biggest angle (in degrees)?
  32. 32.In an isosceles triangle, the two equal angles are 28° each. What is the third angle (in degrees)?
  33. 33.In triangle ABC, angle A = 51° and angle B = 101°. What is angle C (in degrees)?
  34. 34.In triangle ABC, angle A = 45° and angle B = 35°. What is angle C (in degrees)?
  35. 35.In a right-angled triangle, one of the other two angles is 73°. What is the third angle (in degrees)?
  36. 36.The two interior opposite angles of a triangle are 30° and 72°. What is the exterior angle (in degrees)?
  37. 37.In triangle ABC, angle A = 37° and angle B = 43°. What is angle C (in degrees)?
  38. 38.Can a triangle have sides of 15 cm, 6 cm and 6 cm? (a) Yes (b) No
  39. 39.In a right-angled triangle, one of the other two angles is 27°. What is the third angle (in degrees)?
  40. 40.The two interior opposite angles of a triangle are 75° and 48°. What is the exterior angle (in degrees)?

Answer key

  1. 10
  2. 113
  3. 25
  4. 60
  5. No
  6. 37
  7. 46
  8. 40
  9. 15
  10. 45
  11. 34
  12. Yes
  13. 109
  14. 68
  15. 35
  16. 44
  17. 72
  18. No
  19. 77
  20. 80
  21. 39
  22. 27
  23. No
  24. Yes
  25. 90
  26. 7
  27. 38
  28. 58
  29. Yes
  30. No
  31. 100
  32. 124
  33. 28
  34. 100
  35. 17
  36. 102
  37. 100
  38. No
  39. 63
  40. 123

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