← 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 386 · 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 92°. One of its two interior opposite angles is 59°. What is the other one (in degrees)?
  2. 2.The angles of a triangle are in the ratio 1 : 2 : 2. What is the smallest angle (in degrees)?
  3. 3.The angles of a triangle are in the ratio 1 : 2 : 3. What is the biggest angle (in degrees)?
  4. 4.The angles of a triangle are in the ratio 5 : 6 : 7. What is the biggest angle (in degrees)?
  5. 5.In an isosceles triangle, the angle between the two equal sides is 88°. What is each of the other two angles (in degrees)?
  6. 6.The angles of a triangle are in the ratio 5 : 6 : 7. What is the smallest angle (in degrees)?
  7. 7.The angles of a triangle are in the ratio 1 : 2 : 6. What is the biggest angle (in degrees)?
  8. 8.Can a triangle have sides of 11 cm, 26 cm and 10 cm? (a) Yes (b) No
  9. 9.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)?
  10. 10.In triangle ABC, angle A = 96° and angle B = 33°. What is angle C (in degrees)?
  11. 11.An exterior angle of a triangle is 73°. One of its two interior opposite angles is 37°. What is the other one (in degrees)?
  12. 12.The two interior opposite angles of a triangle are 61° and 24°. What is the exterior angle (in degrees)?
  13. 13.In triangle ABC, angle A = 55° and angle B = 91°. What is angle C (in degrees)?
  14. 14.In triangle ABC, angle A = 39° and angle B = 51°. What is angle C (in degrees)?
  15. 15.An exterior angle of a triangle is 96°. One of its two interior opposite angles is 61°. What is the other one (in degrees)?
  16. 16.The two interior opposite angles of a triangle are 53° and 45°. What is the exterior angle (in degrees)?
  17. 17.An exterior angle of a triangle is 135°. One of its two interior opposite angles is 61°. What is the other one (in degrees)?
  18. 18.The longest side of a right-angled triangle is 26 cm and one of the other sides is 24 cm. How long is the third side (in cm)?
  19. 19.In triangle ABC, angle A = 62° and angle B = 74°. What is angle C (in degrees)?
  20. 20.In a right-angled triangle, one of the other two angles is 31°. What is the third angle (in degrees)?
  21. 21.The two interior opposite angles of a triangle are 49° and 78°. What is the exterior angle (in degrees)?
  22. 22.In an isosceles triangle, the two equal angles are 30° each. What is the third angle (in degrees)?
  23. 23.In an isosceles triangle, the two equal angles are 34° each. What is the third angle (in degrees)?
  24. 24.In an isosceles triangle, the angle between the two equal sides is 52°. What is each of the other two angles (in degrees)?
  25. 25.In a right-angled triangle, one of the other two angles is 37°. What is the third angle (in degrees)?
  26. 26.The two interior opposite angles of a triangle are 47° and 72°. What is the exterior angle (in degrees)?
  27. 27.The two shorter sides of a right-angled triangle are 7 cm and 24 cm. How long is the longest side (in cm)?
  28. 28.The two shorter sides of a right-angled triangle are 15 cm and 36 cm. How long is the longest side (in cm)?
  29. 29.An exterior angle of a triangle is 93°. One of its two interior opposite angles is 23°. What is the other one (in degrees)?
  30. 30.In a right-angled triangle, one of the other two angles is 45°. What is the third angle (in degrees)?
  31. 31.Can a triangle have sides of 13 cm, 11 cm and 4 cm? (a) No (b) Yes
  32. 32.In triangle ABC, angle A = 92° and angle B = 53°. What is angle C (in degrees)?
  33. 33.In a right-angled triangle, one of the other two angles is 65°. What is the third angle (in degrees)?
  34. 34.In an isosceles triangle, the angle between the two equal sides is 142°. What is each of the other two angles (in degrees)?
  35. 35.In an isosceles triangle, the angle between the two equal sides is 116°. What is each of the other two angles (in degrees)?
  36. 36.An exterior angle of a triangle is 73°. One of its two interior opposite angles is 24°. What is the other one (in degrees)?
  37. 37.In an isosceles triangle, the two equal angles are 41° each. What is the third angle (in degrees)?
  38. 38.The angles of a triangle are in the ratio 3 : 3 : 4. What is the smallest angle (in degrees)?
  39. 39.The two interior opposite angles of a triangle are 21° and 49°. What is the exterior angle (in degrees)?
  40. 40.The two shorter sides of a right-angled triangle are 24 cm and 18 cm. How long is the longest side (in cm)?

Answer key

  1. 33
  2. 36
  3. 90
  4. 70
  5. 46
  6. 50
  7. 120
  8. No
  9. 7
  10. 51
  11. 36
  12. 85
  13. 34
  14. 90
  15. 35
  16. 98
  17. 74
  18. 10
  19. 44
  20. 59
  21. 127
  22. 120
  23. 112
  24. 64
  25. 53
  26. 119
  27. 25
  28. 39
  29. 70
  30. 45
  31. Yes
  32. 35
  33. 25
  34. 19
  35. 32
  36. 49
  37. 98
  38. 54
  39. 70
  40. 30

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