← 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 826 · 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 9 cm, 10 cm and 2 cm? (a) No (b) Yes
  2. 2.The two interior opposite angles of a triangle are 39° and 35°. What is the exterior angle (in degrees)?
  3. 3.The angles of a triangle are in the ratio 3 : 4 : 5. What is the smallest angle (in degrees)?
  4. 4.Can a triangle have sides of 8 cm, 8 cm and 5 cm? (a) No (b) Yes
  5. 5.In a right-angled triangle, one of the other two angles is 58°. What is the third angle (in degrees)?
  6. 6.In a right-angled triangle, one of the other two angles is 57°. What is the third angle (in degrees)?
  7. 7.In triangle ABC, angle A = 55° and angle B = 97°. What is angle C (in degrees)?
  8. 8.In an isosceles triangle, the angle between the two equal sides is 106°. What is each of the other two angles (in degrees)?
  9. 9.The two shorter sides of a right-angled triangle are 7 cm and 24 cm. How long is the longest side (in cm)?
  10. 10.In a right-angled triangle, one of the other two angles is 10°. What is the third angle (in degrees)?
  11. 11.An exterior angle of a triangle is 100°. One of its two interior opposite angles is 74°. What is the other one (in degrees)?
  12. 12.The longest side of a right-angled triangle is 13 cm and one of the other sides is 12 cm. How long is the third side (in cm)?
  13. 13.The angles of a triangle are in the ratio 1 : 1 : 2. What is the biggest angle (in degrees)?
  14. 14.In a right-angled triangle, one of the other two angles is 25°. What is the third angle (in degrees)?
  15. 15.Can a triangle have sides of 18 cm, 8 cm and 8 cm? (a) Yes (b) No
  16. 16.In a right-angled triangle, one of the other two angles is 71°. What is the third angle (in degrees)?
  17. 17.The angles of a triangle are in the ratio 1 : 2 : 3. What is the biggest angle (in degrees)?
  18. 18.The two interior opposite angles of a triangle are 48° and 37°. What is the exterior angle (in degrees)?
  19. 19.An exterior angle of a triangle is 49°. One of its two interior opposite angles is 26°. What is the other one (in degrees)?
  20. 20.The angles of a triangle are in the ratio 4 : 5 : 6. What is the biggest angle (in degrees)?
  21. 21.An exterior angle of a triangle is 118°. One of its two interior opposite angles is 63°. What is the other one (in degrees)?
  22. 22.In a right-angled triangle, one of the other two angles is 49°. What is the third angle (in degrees)?
  23. 23.An exterior angle of a triangle is 108°. One of its two interior opposite angles is 78°. What is the other one (in degrees)?
  24. 24.In a right-angled triangle, one of the other two angles is 27°. What is the third angle (in degrees)?
  25. 25.In an isosceles triangle, the angle between the two equal sides is 28°. What is each of the other two angles (in degrees)?
  26. 26.The two interior opposite angles of a triangle are 41° and 50°. What is the exterior angle (in degrees)?
  27. 27.The two interior opposite angles of a triangle are 42° and 79°. What is the exterior angle (in degrees)?
  28. 28.The two interior opposite angles of a triangle are 77° and 26°. What is the exterior angle (in degrees)?
  29. 29.In a right-angled triangle, one of the other two angles is 12°. What is the third angle (in degrees)?
  30. 30.An exterior angle of a triangle is 96°. One of its two interior opposite angles is 40°. What is the other one (in degrees)?
  31. 31.The angles of a triangle are in the ratio 2 : 3 : 4. What is the smallest angle (in degrees)?
  32. 32.The angles of a triangle are in the ratio 2 : 3 : 5. What is the smallest angle (in degrees)?
  33. 33.In a right-angled triangle, one of the other two angles is 67°. What is the third angle (in degrees)?
  34. 34.In a right-angled triangle, one of the other two angles is 77°. What is the third angle (in degrees)?
  35. 35.In a right-angled triangle, one of the other two angles is 68°. What is the third angle (in degrees)?
  36. 36.In an isosceles triangle, the two equal angles are 51° each. What is the third angle (in degrees)?
  37. 37.The two shorter sides of a right-angled triangle are 24 cm and 7 cm. How long is the longest side (in cm)?
  38. 38.An exterior angle of a triangle is 143°. One of its two interior opposite angles is 79°. What is the other one (in degrees)?
  39. 39.In triangle ABC, angle A = 33° and angle B = 117°. What is angle C (in degrees)?
  40. 40.In an isosceles triangle, the two equal angles are 24° each. What is the third angle (in degrees)?

Answer key

  1. Yes
  2. 74
  3. 45
  4. Yes
  5. 32
  6. 33
  7. 28
  8. 37
  9. 25
  10. 80
  11. 26
  12. 5
  13. 90
  14. 65
  15. No
  16. 19
  17. 90
  18. 85
  19. 23
  20. 72
  21. 55
  22. 41
  23. 30
  24. 63
  25. 76
  26. 91
  27. 121
  28. 103
  29. 78
  30. 56
  31. 40
  32. 36
  33. 23
  34. 13
  35. 22
  36. 78
  37. 25
  38. 64
  39. 30
  40. 132

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