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Learning without distractions
  1. 1 8:23 Euclid as the father of geometry | Introduction to Euclidean geometry | Geometry | Khan Academy Khan Academy · 1.6M views
  2. 2 12:58 Basic geometry: language and labels | Introduction to Euclidean geometry | Geometry | Khan Academy Khan Academy · 1.9M views
  3. 3 3:38 Intro to lines, line segments, and rays | Geometry | Khan Academy Khan Academy · 1.8M views
  4. 4 11:13 Language and notation of the circle | Introduction to Euclidean geometry | Geometry | Khan Academy Khan Academy · 510.9K views
  5. 5 6:49 Angle basics | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 1.4M views
  6. 6 8:22 Measuring angles in degrees | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 1.1M views
  7. 7 3:26 Measuring angles using a protractor | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 834.8K views
  8. 8 4:05 More angle measurements using a protractor | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 530.2K views
  9. 9 8:31 Complementary and supplementary angles | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 1.5M views
  10. 10 7:19 Introduction to vertical angles | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 805.7K views
  11. 11 4:51 Proof: Vertical angles are equal | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 333.9K views
  12. 12 7:07 Angles formed by parallel lines and transversals | Geometry | Khan Academy Khan Academy · 1.2M views
  13. 13 6:31 Proof – Sum of Measures of Angles in a Triangle are 180 Khan Academy · 197.8K views
  14. 14 6:03 Triangle angle example 1 | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 706.7K views
  15. 15 4:55 Triangle angle example 2 | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 391.1K views
  16. 16 5:42 Triangle angle example 3 | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 290.2K views
  17. 17 8:37 Challenging triangle angle problem | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 223.7K views
  18. 18 5:18 Proof: Corresponding angle equivalence implies parallel lines | Geometry | Khan Academy Khan Academy · 220.1K views
  19. 19 6:05 Finding more angles | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 371.6K views
  20. 20 9:10 Sum of interior angles of a polygon | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 866.6K views
  21. 21 11:29 Congruent triangles and SSS | Congruence | Geometry | Khan Academy Khan Academy · 632K views
  22. 22 8:19 SSS to show a radius is perpendicular to a chord that it bisects | Geometry | Khan Academy Khan Academy · 133.9K views
  23. 23 13:28 Other triangle congruence postulates | Congruence | Geometry | Khan Academy Khan Academy · 420K views
  24. 24 11:06 Two column proof showing segments are perpendicular | Congruence | Geometry | Khan Academy Khan Academy · 318.2K views
  25. 25 5:24 Sum of the exterior angles of convex polygon | Geometry | Khan Academy Khan Academy · 341.8K views
  26. 26 7:28 Finding congruent triangles | Congruence | Geometry | Khan Academy Khan Academy · 379K views
  27. 27 7:24 More on why SSA is not a postulate | Congruence | Geometry | Khan Academy Khan Academy · 186.3K views
  28. 28 5:46 Congruent triangle proof example | Congruence | Geometry | Khan Academy Khan Academy · 342.1K views
  29. 29 12:14 Congruent triangle example 2 | Congruence | Geometry | Khan Academy Khan Academy · 160.9K views
  30. 30 9:03 Congruent legs and base angles of isosceles triangles | Congruence | Geometry | Khan Academy Khan Academy · 303.6K views
  31. 31 6:29 Equilateral triangle sides and angles congruent | Congruence | Geometry | Khan Academy Khan Academy · 150K views
  32. 32 6:27 Equilateral and isosceles example problems | Congruence | Geometry | Khan Academy Khan Academy · 281.7K views
  33. 33 5:34 Another isosceles example problem | Congruence | Geometry | Khan Academy Khan Academy · 116.7K views
  34. 34 3:16 Example involving an isosceles triangle and parallel lines | Congruence | Geometry | Khan Academy Khan Academy · 93.5K views
  35. 35 4:35 Figuring out all the angles for congruent triangles example | Congruence | Geometry | Khan Academy Khan Academy · 152.3K views
  36. 36 8:25 Perimeter and area: the basics | Perimeter, area, and volume | Geometry | Khan Academy Khan Academy · 2.1M views
  37. 37 10:23 Triangle area proofs | Perimeter, area, and volume | Geometry | Khan Academy Khan Academy · 528.3K views
  38. 38 8:13 Interesting perimeter and area problems | Perimeter, area, and volume | Geometry | Khan Academy Khan Academy · 222K views
  39. 39 9:12 Koch snowflake fractal | Perimeter, area, and volume | Geometry | Khan Academy Khan Academy · 268.6K views
  40. 40 3:43 Area of an equilateral triangle | Perimeter, area, and volume | Geometry | Khan Academy Khan Academy · 364.9K views
  41. 41 12:30 Area of Koch snowflake (part 1) – advanced | Perimeter, area, and volume | Geometry | Khan Academy Khan Academy · 108.5K views
  42. 42 6:33 Area of Koch snowflake (part 2) – advanced | Perimeter, area, and volume | Geometry | Khan Academy Khan Academy · 63.9K views
  43. 43 9:56 Challenging perimeter problem | Perimeter, area, and volume | Geometry | Khan Academy Khan Academy · 85K views
  44. 44 9:17 Similar triangle basics | Similarity | Geometry | Khan Academy Khan Academy · 428.3K views
  45. 45 12:14 Similarity postulates | Similarity | Geometry | Khan Academy Khan Academy · 328.9K views
  46. 46 9:24 Similar triangle example problems | Similarity | Geometry | Khan Academy Khan Academy · 268.9K views
  47. 47 7:37 Similarity example problems | Similarity | Geometry | Khan Academy Khan Academy · 752.4K views
  48. 48 9:53 Challenging similarity problem | Similarity | Geometry | Khan Academy Khan Academy · 92.2K views
  49. 49 6:05 Similarity example where same side plays different roles | Similarity | Geometry | Khan Academy Khan Academy · 172.5K views
  50. 50 10:07 Finding area using similarity and congruence | Similarity | Geometry | Khan Academy Khan Academy · 172.6K views
  51. 51 9:53 Pythagorean theorem proof using similarity | Geometry | Khan Academy Khan Academy · 257.2K views
  52. 52 6:59 30-60-90 triangle side ratios proof | Right triangles and trigonometry | Geometry | Khan Academy Khan Academy · 399.3K views
  53. 53 5:42 45-45-90 triangle side ratios | Right triangles and trigonometry | Geometry | Khan Academy Khan Academy · 250.7K views
  54. 54 6:40 30-60-90 triangle example problem | Right triangles and trigonometry | Geometry | Khan Academy Khan Academy · 267K views
  55. 55 14:42 The golden ratio | Introduction to Euclidean geometry | Geometry | Khan Academy Khan Academy · 822.5K views
  56. 56 9:56 Introduction to angles (old) | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 374.5K views
  57. 57 9:05 Angles (part 2) | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 213.2K views
  58. 58 9:48 Angles (part 3) | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 187.9K views
  59. 59 7:53 Angles formed between transversals and parallel lines | Geometry | Khan Academy Khan Academy · 244.6K views
  60. 60 5:15 Angles of parallel lines 2 | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 157.3K views
  61. 61 9:01 The angle game | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 237.8K views
  62. 62 9:34 Similar triangles | Similarity | Geometry | Khan Academy Khan Academy · 695K views
  63. 63 9:55 Similar triangles (part 2) | Similarity | Geometry | Khan Academy Khan Academy · 175.7K views
  64. 64 9:50 Angle game (part 2) | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 110.1K views
  65. 65 5:32 Acute right and obtuse angles | Angles and intersecting lines | Geometry | Khan Academy Khan Academy · 735.7K views
  66. 66 12:20 Area and Perimeter Khan Academy · 504.6K views
  67. 67 11:05 Circles: radius, diameter, circumference and Pi | Geometry | Khan Academy Khan Academy · 2.6M views
  68. 68 6:45 Area of a circle Khan Academy · 357K views
  69. 69 10:46 The Pythagorean theorem intro | Right triangles and trigonometry | Geometry | Khan Academy Khan Academy · 3M views
  70. 70 9:36 Pythagorean theorem II | Right triangles and trigonometry | Geometry | Khan Academy Khan Academy · 277.8K views
  71. 71 9:30 45-45-90 triangles | Right triangles and trigonometry | Geometry | Khan Academy Khan Academy · 681.4K views
  72. 72 9:40 Intro to 30-60-90 triangles | Right triangles and trigonometry | Geometry | Khan Academy Khan Academy · 583.6K views
  73. 73 4:49 30-60-90 Triangles II Khan Academy · 116.9K views
  74. 74 3:56 Find the volume of a triangular prism and cube | Geometry | Khan Academy Khan Academy · 852.9K views
  75. 75 8:07 Cylinder volume and surface area | Perimeter, area, and volume | Geometry | Khan Academy Khan Academy · 1.4M views
  76. 76 4:43 Heron’s formula | Perimeter, area, and volume | Geometry | Khan Academy Khan Academy · 384.1K views
  77. 77 11:00 Part 1 of proof of Heron’s formula | Perimeter, area, and volume | Geometry | Khan Academy Khan Academy · 178.1K views
  78. 78 12:08 Part 2 of proof of Heron’s formula | Perimeter, area, and volume | Geometry | Khan Academy Khan Academy · 104.7K views
  79. 79 14:17 Inscribed angle theorem proof | High School Geometry | High School Math | Khan Academy Khan Academy · 619.2K views
  80. 80 11:39 Area of inscribed equilateral triangle (some basic trig used) | Circles | Geometry | Khan Academy Khan Academy · 299.9K views
  81. 81 5:35 Proof: Right triangles inscribed in circles | High School Math | Khan Academy Khan Academy · 204K views
  82. 82 4:36 Area of diagonal generated triangles of rectangle are equal | Geometry | Khan Academy Khan Academy · 129.5K views
  83. 83 8:59 Triangle medians and centroids | Special properties and parts of triangles | Geometry | Khan Academy Khan Academy · 288.7K views
  84. 84 15:15 Triangle medians and centroids (2D proof) | Geometry | Khan Academy Khan Academy · 76.2K views
  85. 85 4:38 Rhombus diagonals | Quadrilaterals | Geometry | Khan Academy Khan Academy · 156.4K views
  86. 86 13:13 2003 AIME II problem 7 | AIME | Math for fun and glory | Khan Academy Khan Academy · 54K views
  87. 87 6:57 Perpendicular radius bisects chord | Congruence | Geometry | Khan Academy Khan Academy · 115.6K views
  88. 88 12:30 Circumcenter of a triangle | Special properties and parts of triangles | Geometry | Khan Academy Khan Academy · 318.6K views
  89. 89 5:42 Circumcenter of a right triangle | Geometry | Khan Academy Khan Academy · 107.1K views
  90. 90 10:09 Three points defining a circle | Special properties and parts of triangles | Geometry | Khan Academy Khan Academy · 125.3K views
  91. 91 10:57 Point-line distance and angle bisectors | Geometry | Khan Academy Khan Academy · 114.2K views
  92. 92 7:58 Incenter and incircles of a triangle | Geometry | Khan Academy Khan Academy · 177.7K views
  93. 93 8:35 Angle bisector theorem proof | Special properties and parts of triangles | Geometry | Khan Academy Khan Academy · 383.8K views
  94. 94 7:29 Inradius, perimeter, and area | Special properties and parts of triangles | Geometry | Khan Academy Khan Academy · 70.3K views
  95. 95 3:04 Angle bisector theorem examples | Geometry | Khan Academy Khan Academy · 191.8K views
  96. 96 7:46 Medians divide into smaller triangles of equal area | Geometry | Khan Academy Khan Academy · 78.7K views
  97. 97 11:33 Exploring medial triangles | Special properties and parts of triangles | Geometry | Khan Academy Khan Academy · 51.8K views
  98. 98 6:56 Proving that the centroid is 2-3rds along the median | Geometry | Khan Academy Khan Academy · 102.1K views
  99. 99 9:01 Median centroid right triangle example | Geometry | Khan Academy Khan Academy · 61K views
  100. 100 10:01 Proof: Triangle altitudes are concurrent (orthocenter) | Geometry | Khan Academy Khan Academy · 121K views
  101. 101 9:57 Review of triangle properties | Special properties and parts of triangles | Geometry | Khan Academy Khan Academy · 181K views
  102. 102 6:13 Euler line | Special properties and parts of triangles | Geometry | Khan Academy Khan Academy · 98.4K views
  103. 103 9:50 Euler’s line proof | Special properties and parts of triangles | Geometry | Khan Academy Khan Academy · 64.4K views
  104. 104 6:25 Common orthocenter and centroid | Geometry | Khan Academy Khan Academy · 90.1K views
  105. 105 8:24 Quadrilateral overview | Perimeter, area, and volume | Geometry | Khan Academy Khan Academy · 764K views
  106. 106 8:30 Proof: Opposite sides of parallelogram congruent | Quadrilaterals | Geometry | Khan Academy Khan Academy · 309.2K views
  107. 107 9:06 Proof: Diagonals of a parallelogram bisect each other | Quadrilaterals | Geometry | Khan Academy Khan Academy · 330.3K views
  108. 108 4:08 Proof: Opposite angles of parallelogram congruent | Quadrilaterals | Geometry | Khan Academy Khan Academy · 288.3K views
  109. 109 4:04 Proof: Rhombus diagonals are perpendicular bisectors | Quadrilaterals | Geometry | Khan Academy Khan Academy · 183K views
  110. 110 5:07 Proof: Rhombus area half product of diagonal length | Quadrilaterals | Geometry | Khan Academy Khan Academy · 129.3K views
  111. 111 5:42 Area of a parallelogram | Perimeter, area, and volume | Geometry | Khan Academy Khan Academy · 491.7K views
  112. 112 8:16 Problem involving angle derived from square and circle | Congruence | Geometry | Khan Academy Khan Academy · 55.7K views
  113. 113 7:51 Area of a regular hexagon | Right triangles and trigonometry | Geometry | Khan Academy Khan Academy · 414.8K views