← 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 262 · 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 interior opposite angles of a triangle are 24° and 33°. What is the exterior angle (in degrees)?
  2. 2.In triangle ABC, angle A = 100° and angle B = 27°. What is angle C (in degrees)?
  3. 3.In an isosceles triangle, the two equal angles are 29° each. What is the third angle (in degrees)?
  4. 4.The two interior opposite angles of a triangle are 76° and 21°. What is the exterior angle (in degrees)?
  5. 5.The angles of a triangle are in the ratio 1 : 1 : 2. What is the biggest angle (in degrees)?
  6. 6.In a right-angled triangle, one of the other two angles is 21°. What is the third angle (in degrees)?
  7. 7.An exterior angle of a triangle is 96°. One of its two interior opposite angles is 26°. What is the other one (in degrees)?
  8. 8.In triangle ABC, angle A = 86° and angle B = 66°. What is angle C (in degrees)?
  9. 9.In an isosceles triangle, the two equal angles are 82° each. What is the third angle (in degrees)?
  10. 10.In triangle ABC, angle A = 29° and angle B = 21°. What is angle C (in degrees)?
  11. 11.In triangle ABC, angle A = 40° and angle B = 61°. What is angle C (in degrees)?
  12. 12.In an isosceles triangle, the angle between the two equal sides is 124°. What is each of the other two angles (in degrees)?
  13. 13.The two shorter sides of a right-angled triangle are 24 cm and 7 cm. How long is the longest side (in cm)?
  14. 14.The longest side of a right-angled triangle is 26 cm and one of the other sides is 10 cm. How long is the third side (in cm)?
  15. 15.The angles of a triangle are in the ratio 1 : 2 : 2. What is the smallest angle (in degrees)?
  16. 16.Can a triangle have sides of 2 cm, 10 cm and 11 cm? (a) Yes (b) No
  17. 17.In a right-angled triangle, one of the other two angles is 25°. What is the third angle (in degrees)?
  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 1 : 4 : 5. What is the smallest angle (in degrees)?
  20. 20.In triangle ABC, angle A = 36° and angle B = 61°. What is angle C (in degrees)?
  21. 21.The two interior opposite angles of a triangle are 22° and 37°. What is the exterior angle (in degrees)?
  22. 22.The longest side of a right-angled triangle is 17 cm and one of the other sides is 15 cm. How long is the third side (in cm)?
  23. 23.An exterior angle of a triangle is 99°. One of its two interior opposite angles is 25°. What is the other one (in degrees)?
  24. 24.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)?
  25. 25.In triangle ABC, angle A = 93° and angle B = 35°. What is angle C (in degrees)?
  26. 26.An exterior angle of a triangle is 94°. One of its two interior opposite angles is 62°. What is the other one (in degrees)?
  27. 27.The two shorter sides of a right-angled triangle are 4 cm and 3 cm. How long is the longest side (in cm)?
  28. 28.The two shorter sides of a right-angled triangle are 15 cm and 8 cm. How long is the longest side (in cm)?
  29. 29.Can a triangle have sides of 10 cm, 5 cm and 15 cm? (a) Yes (b) No
  30. 30.An exterior angle of a triangle is 118°. One of its two interior opposite angles is 58°. What is the other one (in degrees)?
  31. 31.Can a triangle have sides of 3 cm, 11 cm and 17 cm? (a) Yes (b) No
  32. 32.In an isosceles triangle, the two equal angles are 75° each. What is the third angle (in degrees)?
  33. 33.Can a triangle have sides of 12 cm, 5 cm and 10 cm? (a) No (b) Yes
  34. 34.The angles of a triangle are in the ratio 2 : 2 : 5. What is the biggest angle (in degrees)?
  35. 35.In a right-angled triangle, one of the other two angles is 57°. What is the third angle (in degrees)?
  36. 36.The two interior opposite angles of a triangle are 35° and 40°. What is the exterior angle (in degrees)?
  37. 37.Can a triangle have sides of 6 cm, 2 cm and 6 cm? (a) Yes (b) No
  38. 38.Can a triangle have sides of 17 cm, 6 cm and 7 cm? (a) Yes (b) No
  39. 39.In triangle ABC, angle A = 89° and angle B = 57°. What is angle C (in degrees)?
  40. 40.In a right-angled triangle, one of the other two angles is 67°. What is the third angle (in degrees)?

Answer key

  1. 57
  2. 53
  3. 122
  4. 97
  5. 90
  6. 69
  7. 70
  8. 28
  9. 16
  10. 130
  11. 79
  12. 28
  13. 25
  14. 24
  15. 36
  16. Yes
  17. 65
  18. 13
  19. 18
  20. 83
  21. 59
  22. 8
  23. 74
  24. 24
  25. 52
  26. 32
  27. 5
  28. 17
  29. No
  30. 60
  31. No
  32. 30
  33. Yes
  34. 100
  35. 33
  36. 75
  37. Yes
  38. No
  39. 34
  40. 23

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