← 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 493 · 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 4 cm, 12 cm and 5 cm? (a) No (b) Yes
  2. 2.The two shorter sides of a right-angled triangle are 12 cm and 9 cm. How long is the longest side (in cm)?
  3. 3.In an isosceles triangle, the angle between the two equal sides is 146°. What is each of the other two angles (in degrees)?
  4. 4.In a right-angled triangle, one of the other two angles is 53°. What is the third angle (in degrees)?
  5. 5.In a right-angled triangle, one of the other two angles is 22°. What is the third angle (in degrees)?
  6. 6.In an isosceles triangle, the angle between the two equal sides is 126°. What is each of the other two angles (in degrees)?
  7. 7.The two interior opposite angles of a triangle are 36° and 49°. What is the exterior angle (in degrees)?
  8. 8.Can a triangle have sides of 11 cm, 8 cm and 11 cm? (a) Yes (b) No
  9. 9.Can a triangle have sides of 9 cm, 22 cm and 10 cm? (a) Yes (b) No
  10. 10.The two interior opposite angles of a triangle are 24° and 68°. What is the exterior angle (in degrees)?
  11. 11.In triangle ABC, angle A = 89° and angle B = 27°. What is angle C (in degrees)?
  12. 12.The angles of a triangle are in the ratio 2 : 2 : 5. What is the biggest angle (in degrees)?
  13. 13.The two shorter sides of a right-angled triangle are 8 cm and 6 cm. How long is the longest side (in cm)?
  14. 14.The two shorter sides of a right-angled triangle are 8 cm and 15 cm. How long is the longest side (in cm)?
  15. 15.Can a triangle have sides of 21 cm, 9 cm and 9 cm? (a) Yes (b) No
  16. 16.An exterior angle of a triangle is 112°. One of its two interior opposite angles is 78°. What is the other one (in degrees)?
  17. 17.An exterior angle of a triangle is 81°. One of its two interior opposite angles is 45°. What is the other one (in degrees)?
  18. 18.In a right-angled triangle, one of the other two angles is 15°. What is the third angle (in degrees)?
  19. 19.In an isosceles triangle, the angle between the two equal sides is 144°. What is each of the other two angles (in degrees)?
  20. 20.An exterior angle of a triangle is 105°. One of its two interior opposite angles is 61°. What is the other one (in degrees)?
  21. 21.In an isosceles triangle, the two equal angles are 80° each. What is the third angle (in degrees)?
  22. 22.The angles of a triangle are in the ratio 1 : 1 : 2. What is the smallest angle (in degrees)?
  23. 23.The angles of a triangle are in the ratio 1 : 2 : 3. What is the smallest angle (in degrees)?
  24. 24.Can a triangle have sides of 10 cm, 9 cm and 2 cm? (a) No (b) Yes
  25. 25.In an isosceles triangle, the angle between the two equal sides is 36°. What is each of the other two angles (in degrees)?
  26. 26.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)?
  27. 27.The longest side of a right-angled triangle is 20 cm and one of the other sides is 16 cm. How long is the third side (in cm)?
  28. 28.An exterior angle of a triangle is 150°. One of its two interior opposite angles is 70°. What is the other one (in degrees)?
  29. 29.An exterior angle of a triangle is 91°. One of its two interior opposite angles is 71°. What is the other one (in degrees)?
  30. 30.In triangle ABC, angle A = 33° and angle B = 78°. What is angle C (in degrees)?
  31. 31.In an isosceles triangle, the two equal angles are 25° each. What is the third angle (in degrees)?
  32. 32.An exterior angle of a triangle is 122°. One of its two interior opposite angles is 67°. What is the other one (in degrees)?
  33. 33.Can a triangle have sides of 9 cm, 12 cm and 3 cm? (a) Yes (b) No
  34. 34.Can a triangle have sides of 2 cm, 2 cm and 7 cm? (a) No (b) Yes
  35. 35.In an isosceles triangle, the angle between the two equal sides is 54°. What is each of the other two angles (in degrees)?
  36. 36.In triangle ABC, angle A = 83° and angle B = 41°. What is angle C (in degrees)?
  37. 37.Can a triangle have sides of 15 cm, 8 cm and 8 cm? (a) No (b) Yes
  38. 38.The two interior opposite angles of a triangle are 37° and 76°. What is the exterior angle (in degrees)?
  39. 39.In triangle ABC, angle A = 29° and angle B = 73°. What is angle C (in degrees)?
  40. 40.The angles of a triangle are in the ratio 2 : 7 : 9. What is the biggest angle (in degrees)?

Answer key

  1. No
  2. 15
  3. 17
  4. 37
  5. 68
  6. 27
  7. 85
  8. Yes
  9. No
  10. 92
  11. 64
  12. 100
  13. 10
  14. 17
  15. No
  16. 34
  17. 36
  18. 75
  19. 18
  20. 44
  21. 20
  22. 45
  23. 30
  24. Yes
  25. 72
  26. 15
  27. 12
  28. 80
  29. 20
  30. 69
  31. 130
  32. 55
  33. No
  34. No
  35. 63
  36. 56
  37. Yes
  38. 113
  39. 78
  40. 90

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