← 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 957 · 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 an isosceles triangle, the angle between the two equal sides is 140°. What is each of the other two angles (in degrees)?
  2. 2.An exterior angle of a triangle is 58°. One of its two interior opposite angles is 26°. What is the other one (in degrees)?
  3. 3.The angles of a triangle are in the ratio 1 : 2 : 2. What is the biggest angle (in degrees)?
  4. 4.In triangle ABC, angle A = 37° and angle B = 60°. What is angle C (in degrees)?
  5. 5.The two interior opposite angles of a triangle are 23° and 78°. What is the exterior angle (in degrees)?
  6. 6.In an isosceles triangle, the angle between the two equal sides is 88°. What is each of the other two angles (in degrees)?
  7. 7.The angles of a triangle are in the ratio 3 : 4 : 5. What is the biggest angle (in degrees)?
  8. 8.The angles of a triangle are in the ratio 1 : 4 : 5. What is the smallest angle (in degrees)?
  9. 9.In an isosceles triangle, the angle between the two equal sides is 102°. What is each of the other two angles (in degrees)?
  10. 10.Can a triangle have sides of 25 cm, 10 cm and 10 cm? (a) No (b) Yes
  11. 11.The two shorter sides of a right-angled triangle are 8 cm and 15 cm. How long is the longest side (in cm)?
  12. 12.In a right-angled triangle, one of the other two angles is 72°. What is the third angle (in degrees)?
  13. 13.In an isosceles triangle, the angle between the two equal sides is 134°. What is each of the other two angles (in degrees)?
  14. 14.The longest side of a right-angled triangle is 30 cm and one of the other sides is 18 cm. How long is the third side (in cm)?
  15. 15.Can a triangle have sides of 6 cm, 13 cm and 4 cm? (a) No (b) Yes
  16. 16.In triangle ABC, angle A = 29° and angle B = 91°. What is angle C (in degrees)?
  17. 17.Can a triangle have sides of 7 cm, 5 cm and 15 cm? (a) Yes (b) No
  18. 18.In an isosceles triangle, the two equal angles are 64° each. What is the third angle (in degrees)?
  19. 19.The angles of a triangle are in the ratio 2 : 3 : 5. What is the biggest angle (in degrees)?
  20. 20.In a right-angled triangle, one of the other two angles is 30°. What is the third angle (in degrees)?
  21. 21.In triangle ABC, angle A = 88° and angle B = 22°. What is angle C (in degrees)?
  22. 22.In a right-angled triangle, one of the other two angles is 32°. What is the third angle (in degrees)?
  23. 23.An exterior angle of a triangle is 89°. One of its two interior opposite angles is 20°. What is the other one (in degrees)?
  24. 24.In triangle ABC, angle A = 54° and angle B = 102°. What is angle C (in degrees)?
  25. 25.In an isosceles triangle, the angle between the two equal sides is 50°. What is each of the other two angles (in degrees)?
  26. 26.Can a triangle have sides of 8 cm, 8 cm and 3 cm? (a) Yes (b) No
  27. 27.The angles of a triangle are in the ratio 3 : 5 : 7. What is the biggest angle (in degrees)?
  28. 28.The two shorter sides of a right-angled triangle are 5 cm and 12 cm. How long is the longest side (in cm)?
  29. 29.The two interior opposite angles of a triangle are 43° and 62°. What is the exterior angle (in degrees)?
  30. 30.In an isosceles triangle, the two equal angles are 53° each. What is the third angle (in degrees)?
  31. 31.In triangle ABC, angle A = 94° and angle B = 45°. What is angle C (in degrees)?
  32. 32.An exterior angle of a triangle is 90°. One of its two interior opposite angles is 44°. What is the other one (in degrees)?
  33. 33.In triangle ABC, angle A = 32° and angle B = 45°. What is angle C (in degrees)?
  34. 34.Can a triangle have sides of 10 cm, 5 cm and 4 cm? (a) No (b) Yes
  35. 35.In a right-angled triangle, one of the other two angles is 38°. What is the third angle (in degrees)?
  36. 36.In an isosceles triangle, the angle between the two equal sides is 54°. What is each of the other two angles (in degrees)?
  37. 37.An exterior angle of a triangle is 82°. One of its two interior opposite angles is 61°. What is the other one (in degrees)?
  38. 38.In triangle ABC, angle A = 97° and angle B = 46°. What is angle C (in degrees)?
  39. 39.Can a triangle have sides of 9 cm, 9 cm and 19 cm? (a) Yes (b) No
  40. 40.Can a triangle have sides of 6 cm, 1 cm and 6 cm? (a) Yes (b) No

Answer key

  1. 20
  2. 32
  3. 72
  4. 83
  5. 101
  6. 46
  7. 75
  8. 18
  9. 39
  10. No
  11. 17
  12. 18
  13. 23
  14. 24
  15. No
  16. 60
  17. No
  18. 52
  19. 90
  20. 60
  21. 70
  22. 58
  23. 69
  24. 24
  25. 65
  26. Yes
  27. 84
  28. 13
  29. 105
  30. 74
  31. 41
  32. 46
  33. 103
  34. No
  35. 52
  36. 63
  37. 21
  38. 37
  39. No
  40. Yes

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