← 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 843 · 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.An exterior angle of a triangle is 110°. One of its two interior opposite angles is 58°. What is the other one (in degrees)?
  2. 2.Can a triangle have sides of 8 cm, 9 cm and 3 cm? (a) No (b) Yes
  3. 3.The angles of a triangle are in the ratio 1 : 1 : 2. What is the biggest angle (in degrees)?
  4. 4.The two shorter sides of a right-angled triangle are 15 cm and 8 cm. How long is the longest side (in cm)?
  5. 5.In a right-angled triangle, one of the other two angles is 36°. What is the third angle (in degrees)?
  6. 6.The two shorter sides of a right-angled triangle are 8 cm and 6 cm. How long is the longest side (in cm)?
  7. 7.The two interior opposite angles of a triangle are 71° and 74°. What is the exterior angle (in degrees)?
  8. 8.In a right-angled triangle, one of the other two angles is 15°. What is the third angle (in degrees)?
  9. 9.In a right-angled triangle, one of the other two angles is 34°. What is the third angle (in degrees)?
  10. 10.In an isosceles triangle, the two equal angles are 24° each. What is the third angle (in degrees)?
  11. 11.The longest side of a right-angled triangle is 17 cm and one of the other sides is 8 cm. How long is the third side (in cm)?
  12. 12.An exterior angle of a triangle is 42°. One of its two interior opposite angles is 20°. What is the other one (in degrees)?
  13. 13.In triangle ABC, angle A = 41° and angle B = 60°. What is angle C (in degrees)?
  14. 14.The longest side of a right-angled triangle is 30 cm and one of the other sides is 24 cm. How long is the third side (in cm)?
  15. 15.The two shorter sides of a right-angled triangle are 8 cm and 15 cm. How long is the longest side (in cm)?
  16. 16.In triangle ABC, angle A = 72° and angle B = 83°. What is angle C (in degrees)?
  17. 17.The two interior opposite angles of a triangle are 52° and 58°. What is the exterior angle (in degrees)?
  18. 18.In an isosceles triangle, the two equal angles are 85° each. What is the third angle (in degrees)?
  19. 19.In a right-angled triangle, one of the other two angles is 57°. What is the third angle (in degrees)?
  20. 20.In a right-angled triangle, one of the other two angles is 25°. What is the third angle (in degrees)?
  21. 21.The angles of a triangle are in the ratio 2 : 3 : 5. What is the biggest angle (in degrees)?
  22. 22.The two interior opposite angles of a triangle are 78° and 22°. What is the exterior angle (in degrees)?
  23. 23.The angles of a triangle are in the ratio 3 : 5 : 7. What is the biggest angle (in degrees)?
  24. 24.In a right-angled triangle, one of the other two angles is 13°. What is the third angle (in degrees)?
  25. 25.An exterior angle of a triangle is 121°. One of its two interior opposite angles is 69°. What is the other one (in degrees)?
  26. 26.The two shorter sides of a right-angled triangle are 10 cm and 24 cm. How long is the longest side (in cm)?
  27. 27.The two interior opposite angles of a triangle are 52° and 39°. What is the exterior angle (in degrees)?
  28. 28.Can a triangle have sides of 13 cm, 3 cm and 8 cm? (a) Yes (b) No
  29. 29.In triangle ABC, angle A = 39° and angle B = 43°. What is angle C (in degrees)?
  30. 30.The angles of a triangle are in the ratio 1 : 3 : 5. What is the biggest angle (in degrees)?
  31. 31.Can a triangle have sides of 9 cm, 16 cm and 4 cm? (a) No (b) Yes
  32. 32.In an isosceles triangle, the angle between the two equal sides is 56°. What is each of the other two angles (in degrees)?
  33. 33.The two interior opposite angles of a triangle are 64° and 62°. What is the exterior angle (in degrees)?
  34. 34.Can a triangle have sides of 14 cm, 9 cm and 10 cm? (a) Yes (b) No
  35. 35.In triangle ABC, angle A = 88° and angle B = 51°. What is angle C (in degrees)?
  36. 36.The angles of a triangle are in the ratio 1 : 4 : 5. What is the smallest angle (in degrees)?
  37. 37.In a right-angled triangle, one of the other two angles is 20°. What is the third angle (in degrees)?
  38. 38.In triangle ABC, angle A = 20° and angle B = 107°. What is angle C (in degrees)?
  39. 39.Can a triangle have sides of 8 cm, 16 cm and 8 cm? (a) No (b) Yes
  40. 40.Can a triangle have sides of 6 cm, 4 cm and 7 cm? (a) Yes (b) No

Answer key

  1. 52
  2. Yes
  3. 90
  4. 17
  5. 54
  6. 10
  7. 145
  8. 75
  9. 56
  10. 132
  11. 15
  12. 22
  13. 79
  14. 18
  15. 17
  16. 25
  17. 110
  18. 10
  19. 33
  20. 65
  21. 90
  22. 100
  23. 84
  24. 77
  25. 52
  26. 26
  27. 91
  28. No
  29. 98
  30. 100
  31. No
  32. 62
  33. 126
  34. Yes
  35. 41
  36. 18
  37. 70
  38. 53
  39. No
  40. Yes

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