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Class 7 Maths Worksheet: Triangles

Maths worksheets lesson 53: Triangles: angle sum, exterior angle and Pythagoras · Set 445 · 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.Can a triangle have sides of 10 cm, 10 cm and 24 cm? (a) Yes (b) No
  2. 2.The two interior opposite angles of a triangle are 38° and 77°. What is the exterior angle (in degrees)?
  3. 3.An exterior angle of a triangle is 58°. One of its two interior opposite angles is 26°. What is the other one (in degrees)?
  4. 4.In a right-angled triangle, one of the other two angles is 59°. What is the third angle (in degrees)?
  5. 5.In triangle ABC, angle A = 88° and angle B = 31°. What is angle C (in degrees)?
  6. 6.In triangle ABC, angle A = 47° and angle B = 35°. What is angle C (in degrees)?
  7. 7.In a right-angled triangle, one of the other two angles is 80°. What is the third angle (in degrees)?
  8. 8.Can a triangle have sides of 11 cm, 21 cm and 10 cm? (a) Yes (b) No
  9. 9.The two shorter sides of a right-angled triangle are 15 cm and 36 cm. How long is the longest side (in cm)?
  10. 10.The two interior opposite angles of a triangle are 27° and 39°. What is the exterior angle (in degrees)?
  11. 11.The angles of a triangle are in the ratio 2 : 3 : 4. What is the biggest angle (in degrees)?
  12. 12.Can a triangle have sides of 9 cm, 17 cm and 6 cm? (a) No (b) Yes
  13. 13.The two shorter sides of a right-angled triangle are 12 cm and 9 cm. How long is the longest side (in cm)?
  14. 14.An exterior angle of a triangle is 88°. One of its two interior opposite angles is 25°. What is the other one (in degrees)?
  15. 15.In an isosceles triangle, the angle between the two equal sides is 58°. What is each of the other two angles (in degrees)?
  16. 16.Can a triangle have sides of 22 cm, 10 cm and 12 cm? (a) No (b) Yes
  17. 17.Can a triangle have sides of 9 cm, 10 cm and 24 cm? (a) Yes (b) No
  18. 18.Can a triangle have sides of 16 cm, 11 cm and 2 cm? (a) No (b) Yes
  19. 19.The two interior opposite angles of a triangle are 23° and 73°. What is the exterior angle (in degrees)?
  20. 20.In an isosceles triangle, the angle between the two equal sides is 130°. What is each of the other two angles (in degrees)?
  21. 21.In triangle ABC, angle A = 98° and angle B = 36°. What is angle C (in degrees)?
  22. 22.Can a triangle have sides of 10 cm, 19 cm and 5 cm? (a) No (b) Yes
  23. 23.An exterior angle of a triangle is 152°. One of its two interior opposite angles is 80°. What is the other one (in degrees)?
  24. 24.The two interior opposite angles of a triangle are 71° and 43°. What is the exterior angle (in degrees)?
  25. 25.The two shorter sides of a right-angled triangle are 20 cm and 15 cm. How long is the longest side (in cm)?
  26. 26.The longest side of a right-angled triangle is 15 cm and one of the other sides is 12 cm. How long is the third side (in cm)?
  27. 27.In an isosceles triangle, the two equal angles are 26° each. What is the third angle (in degrees)?
  28. 28.The longest side of a right-angled triangle is 25 cm and one of the other sides is 7 cm. How long is the third side (in cm)?
  29. 29.Can a triangle have sides of 12 cm, 19 cm and 4 cm? (a) No (b) Yes
  30. 30.An exterior angle of a triangle is 94°. One of its two interior opposite angles is 38°. What is the other one (in degrees)?
  31. 31.In triangle ABC, angle A = 30° and angle B = 105°. What is angle C (in degrees)?
  32. 32.In a right-angled triangle, one of the other two angles is 43°. What is the third angle (in degrees)?
  33. 33.In triangle ABC, angle A = 82° and angle B = 59°. What is angle C (in degrees)?
  34. 34.Can a triangle have sides of 4 cm, 11 cm and 4 cm? (a) No (b) Yes
  35. 35.In a right-angled triangle, one of the other two angles is 47°. What is the third angle (in degrees)?
  36. 36.The angles of a triangle are in the ratio 1 : 2 : 2. What is the biggest angle (in degrees)?
  37. 37.In a right-angled triangle, one of the other two angles is 55°. What is the third angle (in degrees)?
  38. 38.In triangle ABC, angle A = 63° and angle B = 94°. What is angle C (in degrees)?
  39. 39.In an isosceles triangle, the angle between the two equal sides is 30°. What is each of the other two angles (in degrees)?
  40. 40.In triangle ABC, angle A = 62° and angle B = 65°. What is angle C (in degrees)?

Answer key

  1. No
  2. 115
  3. 32
  4. 31
  5. 61
  6. 98
  7. 10
  8. No
  9. 39
  10. 66
  11. 80
  12. No
  13. 15
  14. 63
  15. 61
  16. No
  17. No
  18. No
  19. 96
  20. 25
  21. 46
  22. No
  23. 72
  24. 114
  25. 25
  26. 9
  27. 128
  28. 24
  29. No
  30. 56
  31. 45
  32. 47
  33. 39
  34. No
  35. 43
  36. 72
  37. 35
  38. 23
  39. 75
  40. 53

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