← 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 903 · 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 11 cm, 12 cm and 10 cm? (a) No (b) Yes
  2. 2.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)?
  3. 3.The angles of a triangle are in the ratio 1 : 2 : 2. What is the biggest angle (in degrees)?
  4. 4.The angles of a triangle are in the ratio 3 : 5 : 7. What is the biggest angle (in degrees)?
  5. 5.The two interior opposite angles of a triangle are 77° and 37°. What is the exterior angle (in degrees)?
  6. 6.In triangle ABC, angle A = 33° and angle B = 23°. What is angle C (in degrees)?
  7. 7.The longest side of a right-angled triangle is 25 cm and one of the other sides is 15 cm. How long is the third side (in cm)?
  8. 8.In triangle ABC, angle A = 38° and angle B = 112°. What is angle C (in degrees)?
  9. 9.In triangle ABC, angle A = 29° and angle B = 91°. What is angle C (in degrees)?
  10. 10.In triangle ABC, angle A = 44° and angle B = 46°. What is angle C (in degrees)?
  11. 11.In an isosceles triangle, the angle between the two equal sides is 138°. What is each of the other two angles (in degrees)?
  12. 12.In an isosceles triangle, the two equal angles are 77° each. What is the third angle (in degrees)?
  13. 13.Can a triangle have sides of 6 cm, 8 cm and 5 cm? (a) No (b) Yes
  14. 14.The two shorter sides of a right-angled triangle are 36 cm and 15 cm. How long is the longest side (in cm)?
  15. 15.In triangle ABC, angle A = 42° and angle B = 74°. What is angle C (in degrees)?
  16. 16.In an isosceles triangle, the angle between the two equal sides is 68°. What is each of the other two angles (in degrees)?
  17. 17.The angles of a triangle are in the ratio 3 : 5 : 7. What is the smallest angle (in degrees)?
  18. 18.In triangle ABC, angle A = 64° and angle B = 51°. What is angle C (in degrees)?
  19. 19.The angles of a triangle are in the ratio 1 : 3 : 5. What is the biggest angle (in degrees)?
  20. 20.Can a triangle have sides of 9 cm, 2 cm and 13 cm? (a) Yes (b) No
  21. 21.In a right-angled triangle, one of the other two angles is 68°. What is the third angle (in degrees)?
  22. 22.The longest side of a right-angled triangle is 25 cm and one of the other sides is 24 cm. How long is the third side (in cm)?
  23. 23.In triangle ABC, angle A = 59° and angle B = 54°. What is angle C (in degrees)?
  24. 24.The two interior opposite angles of a triangle are 61° and 65°. What is the exterior angle (in degrees)?
  25. 25.An exterior angle of a triangle is 107°. One of its two interior opposite angles is 46°. What is the other one (in degrees)?
  26. 26.Can a triangle have sides of 6 cm, 16 cm and 7 cm? (a) No (b) Yes
  27. 27.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)?
  28. 28.An exterior angle of a triangle is 65°. One of its two interior opposite angles is 23°. What is the other one (in degrees)?
  29. 29.Can a triangle have sides of 9 cm, 18 cm and 7 cm? (a) No (b) Yes
  30. 30.The longest side of a right-angled triangle is 39 cm and one of the other sides is 15 cm. How long is the third side (in cm)?
  31. 31.In triangle ABC, angle A = 89° and angle B = 34°. What is angle C (in degrees)?
  32. 32.In triangle ABC, angle A = 50° and angle B = 105°. What is angle C (in degrees)?
  33. 33.In an isosceles triangle, the angle between the two equal sides is 50°. What is each of the other two angles (in degrees)?
  34. 34.An exterior angle of a triangle is 145°. One of its two interior opposite angles is 80°. What is the other one (in degrees)?
  35. 35.An exterior angle of a triangle is 57°. One of its two interior opposite angles is 27°. What is the other one (in degrees)?
  36. 36.In triangle ABC, angle A = 62° and angle B = 64°. What is angle C (in degrees)?
  37. 37.In an isosceles triangle, the two equal angles are 64° each. What is the third angle (in degrees)?
  38. 38.The two shorter sides of a right-angled triangle are 7 cm and 24 cm. How long is the longest side (in cm)?
  39. 39.Can a triangle have sides of 8 cm, 11 cm and 14 cm? (a) No (b) Yes
  40. 40.Can a triangle have sides of 11 cm, 12 cm and 4 cm? (a) Yes (b) No

Answer key

  1. Yes
  2. 24
  3. 72
  4. 84
  5. 114
  6. 124
  7. 20
  8. 30
  9. 60
  10. 90
  11. 21
  12. 26
  13. Yes
  14. 39
  15. 64
  16. 56
  17. 36
  18. 65
  19. 100
  20. No
  21. 22
  22. 7
  23. 67
  24. 126
  25. 61
  26. No
  27. 15
  28. 42
  29. No
  30. 36
  31. 57
  32. 25
  33. 65
  34. 65
  35. 30
  36. 54
  37. 52
  38. 25
  39. Yes
  40. Yes

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