← 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 917 · 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 shorter sides of a right-angled triangle are 8 cm and 15 cm. How long is the longest side (in cm)?
  2. 2.Can a triangle have sides of 9 cm, 25 cm and 12 cm? (a) Yes (b) No
  3. 3.The angles of a triangle are in the ratio 4 : 5 : 6. What is the biggest angle (in degrees)?
  4. 4.The two interior opposite angles of a triangle are 35° and 69°. What is the exterior angle (in degrees)?
  5. 5.Can a triangle have sides of 12 cm, 4 cm and 4 cm? (a) No (b) Yes
  6. 6.The two shorter sides of a right-angled triangle are 7 cm and 24 cm. How long is the longest side (in cm)?
  7. 7.An exterior angle of a triangle is 70°. One of its two interior opposite angles is 26°. What is the other one (in degrees)?
  8. 8.The angles of a triangle are in the ratio 2 : 7 : 9. What is the biggest angle (in degrees)?
  9. 9.Can a triangle have sides of 14 cm, 9 cm and 6 cm? (a) No (b) Yes
  10. 10.An exterior angle of a triangle is 103°. One of its two interior opposite angles is 31°. What is the other one (in degrees)?
  11. 11.The angles of a triangle are in the ratio 3 : 3 : 4. What is the biggest angle (in degrees)?
  12. 12.Can a triangle have sides of 7 cm, 4 cm and 10 cm? (a) No (b) Yes
  13. 13.In triangle ABC, angle A = 79° and angle B = 70°. What is angle C (in degrees)?
  14. 14.The two interior opposite angles of a triangle are 69° and 57°. What is the exterior angle (in degrees)?
  15. 15.In triangle ABC, angle A = 30° and angle B = 106°. What is angle C (in degrees)?
  16. 16.Can a triangle have sides of 16 cm, 10 cm and 3 cm? (a) Yes (b) No
  17. 17.An exterior angle of a triangle is 52°. One of its two interior opposite angles is 20°. What is the other one (in degrees)?
  18. 18.The two shorter sides of a right-angled triangle are 12 cm and 9 cm. How long is the longest side (in cm)?
  19. 19.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)?
  20. 20.The angles of a triangle are in the ratio 1 : 3 : 5. What is the biggest angle (in degrees)?
  21. 21.Can a triangle have sides of 2 cm, 4 cm and 6 cm? (a) No (b) Yes
  22. 22.The angles of a triangle are in the ratio 1 : 1 : 2. What is the biggest angle (in degrees)?
  23. 23.In an isosceles triangle, the angle between the two equal sides is 90°. What is each of the other two angles (in degrees)?
  24. 24.The two interior opposite angles of a triangle are 40° and 55°. What is the exterior angle (in degrees)?
  25. 25.The angles of a triangle are in the ratio 4 : 5 : 6. What is the smallest angle (in degrees)?
  26. 26.In triangle ABC, angle A = 41° and angle B = 33°. What is angle C (in degrees)?
  27. 27.The angles of a triangle are in the ratio 3 : 4 : 5. What is the biggest angle (in degrees)?
  28. 28.In a right-angled triangle, one of the other two angles is 33°. What is the third angle (in degrees)?
  29. 29.The angles of a triangle are in the ratio 2 : 2 : 5. What is the smallest angle (in degrees)?
  30. 30.In a right-angled triangle, one of the other two angles is 56°. What is the third angle (in degrees)?
  31. 31.Can a triangle have sides of 5 cm, 13 cm and 8 cm? (a) Yes (b) No
  32. 32.In a right-angled triangle, one of the other two angles is 21°. What is the third angle (in degrees)?
  33. 33.The two interior opposite angles of a triangle are 28° and 62°. What is the exterior angle (in degrees)?
  34. 34.In an isosceles triangle, the angle between the two equal sides is 152°. What is each of the other two angles (in degrees)?
  35. 35.In an isosceles triangle, the two equal angles are 65° each. What is the third angle (in degrees)?
  36. 36.The two shorter sides of a right-angled triangle are 24 cm and 7 cm. How long is the longest side (in cm)?
  37. 37.Can a triangle have sides of 5 cm, 11 cm and 6 cm? (a) Yes (b) No
  38. 38.In triangle ABC, angle A = 20° and angle B = 116°. What is angle C (in degrees)?
  39. 39.In an isosceles triangle, the two equal angles are 57° each. What is the third angle (in degrees)?
  40. 40.An exterior angle of a triangle is 79°. One of its two interior opposite angles is 59°. What is the other one (in degrees)?

Answer key

  1. 17
  2. No
  3. 72
  4. 104
  5. No
  6. 25
  7. 44
  8. 90
  9. Yes
  10. 72
  11. 72
  12. Yes
  13. 31
  14. 126
  15. 44
  16. No
  17. 32
  18. 15
  19. 8
  20. 100
  21. No
  22. 90
  23. 45
  24. 95
  25. 48
  26. 106
  27. 75
  28. 57
  29. 40
  30. 34
  31. No
  32. 69
  33. 90
  34. 14
  35. 50
  36. 25
  37. No
  38. 44
  39. 66
  40. 20

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