Steply

Geometry

68 lessons · 1429 problems solved step by step

  1. Angle facts · line, point, triangle, vertical angles (22 problems)
  2. Complementary and supplementary angles (22 problems)
  3. Classifying angles and triangles (23 problems)
  4. Can it make a triangle · the two short sides must be longer than the longest; the third side between (20 problems)
  5. Exterior angle of a triangle · the two far inside angles added (20 problems)
  6. Constructions with a ruler and compasses · triangle from 3 sides, perpendicular bisector, angle bisector (20 problems)
  7. Loci · points that follow a rule (circle, perpendicular bisector, angle bisector, regions) (20 problems)
  8. Three-figure bearings and back bearings (20 problems)
  9. Perimeter and area (26 problems)
  10. Work backwards · missing lengths from area, perimeter, circumference (20 problems)
  11. Converting area units (20 problems)
  12. Arc length, sector area and perimeter as a part of the circle (20 problems)
  13. Volume and surface area (23 problems)
  14. Pythagoras (22 problems)
  15. Is it a right triangle? (21 problems)
  16. Special right triangles · 45-45-90 and 30-60-90 (21 problems)
  17. Pythagoras in 3D · the floor diagonal, then the diagonal through the box (20 problems)
  18. Right triangle with its height to the hypotenuse · Euclid's rules (20 problems)
  19. Parallel lines and a transversal · corresponding, alternate, co-interior angles (24 problems)
  20. Are the lines parallel? (20 problems)
  21. Parallelogram and trapezoid · area, perimeter, height from the area (24 problems)
  22. Rhombus and kite · area from the diagonals, angles (20 problems)
  23. Composite shapes · add the parts, take away a hole, perimeter of round ends (23 problems)
  24. More composite shapes · quarter circles, three parts, a triangle cut out, a semicircle on the long side (21 problems)
  25. Prisms · volume and surface area (23 problems)
  26. Pyramids · volume and surface area (21 problems)
  27. Surface area of a rectangular pyramid · two different pairs of triangles (20 problems)
  28. Nets and surface area · unfold it, the area of each face, add them all (20 problems)
  29. Cross sections · the flat face of a cut through a solid (20 problems)
  30. Cones · volume and surface area (21 problems)
  31. Volume of a frustum · big cone − small cone (20 problems)
  32. Spheres and hemispheres · volume and surface area (20 problems)
  33. Similar triangles (20 problems)
  34. Similar shapes and solids · areas × k², volumes × k³ (20 problems)
  35. A line parallel to a side (20 problems)
  36. Scale drawings and maps (20 problems)
  37. Shadow problems (20 problems)
  38. Right-triangle trigonometry · SOH CAH TOA (20 problems)
  39. Angles of elevation and depression (20 problems)
  40. Trigonometry in 3D · the angle between a line and a plane (20 problems)
  41. Bearings with trigonometry and Pythagoras (20 problems)
  42. Distance between two points (24 problems)
  43. Midpoint (24 problems)
  44. Perpendicular bisector of a segment (20 problems)
  45. Equation of a circle (24 problems)
  46. Circle from the general form (20 problems)
  47. Angles in a polygon · angle sum, one angle of a regular polygon, a missing angle (26 problems)
  48. Exterior angles · one exterior angle, how many sides, a missing exterior angle (22 problems)
  49. Circle rules · angle at the center, angle in a semicircle, angles in the same segment (23 problems)
  50. Chords · the line from the center at 90° cuts the chord in half (20 problems)
  51. Intersecting chords, secants and tangents (20 problems)
  52. Congruent triangles · SSS, SAS, ASA, AAS; matching parts (21 problems)
  53. Isosceles triangles · base angles (21 problems)
  54. RHS · right angle, hypotenuse, side (20 problems)
  55. Isosceles triangles with sides, equilateral triangles (21 problems)
  56. Medians and the centroid · the median to the hypotenuse (20 problems)
  57. Cyclic quadrilaterals · opposite angles add up to 180° (20 problems)
  58. Tangents · tangent and radius (90°), two tangents from a point (20 problems)
  59. The alternate segment theorem (20 problems)
  60. Two-column proofs · statements and reasons (20 problems)
  61. Translations · slide every point the same way (21 problems)
  62. Reflections · in the axes, y = x, x = k and y = k (21 problems)
  63. Rotations about the origin · 90°, 180°, 270°, clockwise and counterclockwise (20 problems)
  64. Rotation about a point (20 problems)
  65. Dilations about the origin · multiply by the scale factor (19 problems)
  66. Two moves in a row · describe the move (20 problems)
  67. Glide reflections (20 problems)
  68. Symmetry · lines of symmetry, order of rotational symmetry (25 problems)