← 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 406 · 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.The two interior opposite angles of a triangle are 20° and 63°. What is the exterior angle (in degrees)?
  2. 2.The longest side of a right-angled triangle is 13 cm and one of the other sides is 12 cm. How long is the third side (in cm)?
  3. 3.In a right-angled triangle, one of the other two angles is 36°. What is the third angle (in degrees)?
  4. 4.The angles of a triangle are in the ratio 2 : 2 : 5. What is the smallest angle (in degrees)?
  5. 5.Can a triangle have sides of 11 cm, 6 cm and 10 cm? (a) Yes (b) No
  6. 6.The two interior opposite angles of a triangle are 65° and 45°. What is the exterior angle (in degrees)?
  7. 7.In an isosceles triangle, the two equal angles are 26° each. What is the third angle (in degrees)?
  8. 8.In an isosceles triangle, the two equal angles are 67° each. What is the third angle (in degrees)?
  9. 9.The two shorter sides of a right-angled triangle are 15 cm and 8 cm. How long is the longest side (in cm)?
  10. 10.Can a triangle have sides of 21 cm, 8 cm and 9 cm? (a) Yes (b) No
  11. 11.In triangle ABC, angle A = 92° and angle B = 48°. What is angle C (in degrees)?
  12. 12.In an isosceles triangle, the two equal angles are 52° each. What is the third angle (in degrees)?
  13. 13.The angles of a triangle are in the ratio 3 : 5 : 7. What is the smallest angle (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.Can a triangle have sides of 10 cm, 6 cm and 21 cm? (a) No (b) Yes
  16. 16.In a right-angled triangle, one of the other two angles is 58°. What is the third angle (in degrees)?
  17. 17.In a right-angled triangle, one of the other two angles is 35°. What is the third angle (in degrees)?
  18. 18.The longest side of a right-angled triangle is 17 cm and one of the other sides is 15 cm. How long is the third side (in cm)?
  19. 19.In a right-angled triangle, one of the other two angles is 16°. What is the third angle (in degrees)?
  20. 20.In a right-angled triangle, one of the other two angles is 15°. What is the third angle (in degrees)?
  21. 21.In triangle ABC, angle A = 44° and angle B = 25°. What is angle C (in degrees)?
  22. 22.In triangle ABC, angle A = 94° and angle B = 60°. What is angle C (in degrees)?
  23. 23.The two shorter sides of a right-angled triangle are 24 cm and 7 cm. How long is the longest side (in cm)?
  24. 24.The longest side of a right-angled triangle is 5 cm and one of the other sides is 3 cm. How long is the third side (in cm)?
  25. 25.Can a triangle have sides of 11 cm, 16 cm and 7 cm? (a) No (b) Yes
  26. 26.An exterior angle of a triangle is 92°. One of its two interior opposite angles is 33°. What is the other one (in degrees)?
  27. 27.The angles of a triangle are in the ratio 1 : 3 : 5. What is the biggest angle (in degrees)?
  28. 28.The angles of a triangle are in the ratio 1 : 2 : 3. What is the biggest angle (in degrees)?
  29. 29.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)?
  30. 30.Can a triangle have sides of 12 cm, 18 cm and 3 cm? (a) No (b) Yes
  31. 31.In an isosceles triangle, the two equal angles are 58° each. What is the third angle (in degrees)?
  32. 32.Can a triangle have sides of 12 cm, 25 cm and 8 cm? (a) Yes (b) No
  33. 33.An exterior angle of a triangle is 90°. One of its two interior opposite angles is 43°. What is the other one (in degrees)?
  34. 34.The angles of a triangle are in the ratio 3 : 4 : 5. What is the smallest angle (in degrees)?
  35. 35.In an isosceles triangle, the angle between the two equal sides is 32°. What is each of the other two angles (in degrees)?
  36. 36.In a right-angled triangle, one of the other two angles is 20°. What is the third angle (in degrees)?
  37. 37.Can a triangle have sides of 12 cm, 10 cm and 5 cm? (a) Yes (b) No
  38. 38.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)?
  39. 39.The two shorter sides of a right-angled triangle are 9 cm and 12 cm. How long is the longest side (in cm)?
  40. 40.Can a triangle have sides of 16 cm, 2 cm and 10 cm? (a) Yes (b) No

Answer key

  1. 83
  2. 5
  3. 54
  4. 40
  5. Yes
  6. 110
  7. 128
  8. 46
  9. 17
  10. No
  11. 40
  12. 76
  13. 36
  14. 14
  15. No
  16. 32
  17. 55
  18. 8
  19. 74
  20. 75
  21. 111
  22. 26
  23. 25
  24. 4
  25. Yes
  26. 59
  27. 100
  28. 90
  29. 24
  30. No
  31. 64
  32. No
  33. 47
  34. 45
  35. 74
  36. 70
  37. Yes
  38. 7
  39. 15
  40. No

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