← 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 931 · 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 46°. What is each of the other two angles (in degrees)?
  2. 2.In triangle ABC, angle A = 57° and angle B = 50°. What is angle C (in degrees)?
  3. 3.Can a triangle have sides of 4 cm, 3 cm and 5 cm? (a) No (b) Yes
  4. 4.The two shorter sides of a right-angled triangle are 8 cm and 15 cm. How long is the longest side (in cm)?
  5. 5.The angles of a triangle are in the ratio 1 : 2 : 2. What is the smallest angle (in degrees)?
  6. 6.The two shorter sides of a right-angled triangle are 16 cm and 12 cm. How long is the longest side (in cm)?
  7. 7.The angles of a triangle are in the ratio 3 : 3 : 4. What is the biggest angle (in degrees)?
  8. 8.In an isosceles triangle, the two equal angles are 41° each. What is the third angle (in degrees)?
  9. 9.An exterior angle of a triangle is 151°. One of its two interior opposite angles is 78°. What is the other one (in degrees)?
  10. 10.The angles of a triangle are in the ratio 2 : 3 : 4. What is the biggest angle (in degrees)?
  11. 11.In triangle ABC, angle A = 62° and angle B = 58°. What is angle C (in degrees)?
  12. 12.In triangle ABC, angle A = 44° and angle B = 113°. What is angle C (in degrees)?
  13. 13.In an isosceles triangle, the angle between the two equal sides is 110°. What is each of the other two angles (in degrees)?
  14. 14.In an isosceles triangle, the angle between the two equal sides is 152°. What is each of the other two angles (in degrees)?
  15. 15.In a right-angled triangle, one of the other two angles is 48°. What is the third angle (in degrees)?
  16. 16.Can a triangle have sides of 18 cm, 7 cm and 7 cm? (a) Yes (b) No
  17. 17.The two interior opposite angles of a triangle are 34° and 59°. What is the exterior angle (in degrees)?
  18. 18.In an isosceles triangle, the angle between the two equal sides is 102°. What is each of the other two angles (in degrees)?
  19. 19.In a right-angled triangle, one of the other two angles is 63°. What is the third angle (in degrees)?
  20. 20.The angles of a triangle are in the ratio 1 : 2 : 6. What is the smallest angle (in degrees)?
  21. 21.Can a triangle have sides of 12 cm, 25 cm and 10 cm? (a) Yes (b) No
  22. 22.An exterior angle of a triangle is 108°. One of its two interior opposite angles is 65°. What is the other one (in degrees)?
  23. 23.In an isosceles triangle, the two equal angles are 64° each. What is the third angle (in degrees)?
  24. 24.In an isosceles triangle, the angle between the two equal sides is 96°. What is each of the other two angles (in degrees)?
  25. 25.The angles of a triangle are in the ratio 1 : 4 : 5. What is the smallest angle (in degrees)?
  26. 26.In triangle ABC, angle A = 32° and angle B = 24°. What is angle C (in degrees)?
  27. 27.An exterior angle of a triangle is 96°. One of its two interior opposite angles is 37°. What is the other one (in degrees)?
  28. 28.In an isosceles triangle, the angle between the two equal sides is 126°. What is each of the other two angles (in degrees)?
  29. 29.In an isosceles triangle, the angle between the two equal sides is 52°. What is each of the other two angles (in degrees)?
  30. 30.An exterior angle of a triangle is 98°. One of its two interior opposite angles is 29°. What is the other one (in degrees)?
  31. 31.In triangle ABC, angle A = 94° and angle B = 58°. What is angle C (in degrees)?
  32. 32.In a right-angled triangle, one of the other two angles is 25°. What is the third angle (in degrees)?
  33. 33.An exterior angle of a triangle is 126°. One of its two interior opposite angles is 80°. What is the other one (in degrees)?
  34. 34.An exterior angle of a triangle is 110°. One of its two interior opposite angles is 48°. What is the other one (in degrees)?
  35. 35.An exterior angle of a triangle is 110°. One of its two interior opposite angles is 33°. What is the other one (in degrees)?
  36. 36.In a right-angled triangle, one of the other two angles is 55°. What is the third angle (in degrees)?
  37. 37.The two shorter sides of a right-angled triangle are 15 cm and 8 cm. How long is the longest side (in cm)?
  38. 38.In triangle ABC, angle A = 68° and angle B = 78°. What is angle C (in degrees)?
  39. 39.The two shorter sides of a right-angled triangle are 12 cm and 5 cm. How long is the longest side (in cm)?
  40. 40.The longest side of a right-angled triangle is 10 cm and one of the other sides is 6 cm. How long is the third side (in cm)?

Answer key

  1. 67
  2. 73
  3. Yes
  4. 17
  5. 36
  6. 20
  7. 72
  8. 98
  9. 73
  10. 80
  11. 60
  12. 23
  13. 35
  14. 14
  15. 42
  16. No
  17. 93
  18. 39
  19. 27
  20. 20
  21. No
  22. 43
  23. 52
  24. 42
  25. 18
  26. 124
  27. 59
  28. 27
  29. 64
  30. 69
  31. 28
  32. 65
  33. 46
  34. 62
  35. 77
  36. 35
  37. 17
  38. 34
  39. 13
  40. 8

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