Subject Guides: Math Survival Guide: Geometry & Trigonometry

Online Resources

Lines (Khan Academy) - Opens in a new window
Videos tutorials on lines, line segments, and rays.
Angles (Khan Academy) - Opens in a new window
Video tutorials on angle basics, interpreting angles, and relationships between angles.
Shapes (Khan Academy) - Opens in a new window
Video tutorials on classifying shapes and finding angles in shapes
The coordinate plane (Khan Academy) - Opens in a new window
Video tutorials on the basics of the coordinate plane and shapes on the coordinate plane.
Area and perimeter (Khan Academy) - Opens in a new window
Video tutorials on the area and perimeter of polygons, area and circumference of circles, and scale drawings.
Volume and surface area (Khan Academy) - Opens in a new window
Video tutorials on surface area and the volume of prisms, cones, cylinders, and spheres.
The Pythagorean theorem (Khan Academy) - Opens in a new window
Video tutorials on the Pythagorean theorem, special right triangles, and Pythagorean theorem proofs.
Transformations, congruence, and similarity (Khan Academy) - Opens in a new window
Video tutorials on transformations, congruence, and similarity.

Tools of geometry (Khan Academy) - Opens in a new window
Video tutorials on Euclidean geometry, lines, line segments, rays, points, lines, planes, geometric definitions, and the golden ratio.
Angles & intersecting lines (Khan Academy) - Opens in a new window
Video tutorials on angle basics, angle measurement, angle types, vertical angles, complementary and supplementary angles, angles between intersecting and parallel lines, and angles with triangles and polygons.
Special properties and parts of triangles (Khan Academy) - Opens in a new window
Video tutorials on the triangle inequality theorem, perpendicular bisectors, angle bisectors, medians and centroids, and altitudes.
Quadrilaterals (Khan Academy) - Opens in a new window
Video tutorials on types of quadrilaterals and quadrilateral proofs and angles.
Transformations (Khan Academy) - Opens in a new window
Video tutorials on translations, rotations, reflections, dilations, sequences of transformations, properties and definitions of transformations, and symmetry.
Congruence (Khan Academy) - Opens in a new window
Video tutorials on transformations and congruence, triangle congruence, theorems concerning triangle properties, working with triangles, theorems concerning quadrilateral properties, and proofs of general theorems that use triangle congruence.
Similarity (Khan Academy) - Opens in a new window
Video tutorials on triangle similarity, solving similar triangles, angle bisector theorem, solving problems with similar and congruent triangles, and solving modeling problems with similar and congruent triangles.
Right triangles and trigonometry (Khan Academy) - Opens in a new window
Video tutorials on special right triangles, trigonometric ratios, modeling with right triangles, trigonometric ratios and similarity, sine and cosine of complementary angles, the law of sines, the law of cosines, and solving general triangles.
Circles (Khan Academy) - Opens in a new window
Video tutorials on circle basics, arc measure, arc length, radians, sectors, inscribed angles, inscribed shapes problem solving, properties of tangents, area of an inscribed triangle, standard equation of a circle, and expanded equation of a circle.
Volume and surface area (Khan Academy) - Opens in a new window
Video tutorials on basic area, advanced perimeter and area, area formula proofs, advanced area with triangles, area and circumference of circles, volume and surface area, surface and volume density, cross sections of 3D objects, the Koch snowflake fractal, and Heron's formula.
Analytic geometry (Khan Academy) - Opens in a new window
Video tutorials on distance and midpoints, problem solving with distance on the coordinate plane, dividing line segments, parallel and perpendicular lines on the coordinate plane, equations of parallel and perpendicular lines, coordinate plane proofs, and the equation of a circle.
Geometry at Wolfram MathWorld - Opens in a new window
An extensive, encyclopedia-style resource including definitions and explanations of geometry concepts and terms.

Trigonometry with right triangles (Khan Academy) - Opens in a new window
Video tutorials on trigonometric ratios, modeling with right triangles, sine and cosine of complementary angles, and more.
Trigonometry with general triangles (Khan Academy) - Opens in a new window
Video tutorials on the law of sines, the law of cosines, and solving general triangles.
The unit circle definition of sine, cosine, and tangent (Khan Academy) - Opens in a new window
Video tutorials on radians, the unit circle definition of sine, cosine, and tangent, the graphs of sine, cosine, and tangent, basic trigonometric identities, trigonometric values of special angles, and more.
Graphs of trigonometric functions (Khan Academy) - Opens in a new window
Video tutorials on the graphs of sine, cosine, and tangent, amplitude, midline, and extrema of sinusoidal functions, period of sinusoidal functions, graphing sinusoidal functions, and constructing sinusoidal functions.
Trigonometric equations and identities (Khan Academy) - Opens in a new window
Videos on trig identity reference, inverse trigonometric functions, solving basic and advanced sinusoidal equations, solving sinusoidal models, trigonometric angle addition identities, and using trigonometric identities to solve problems.
Trigonometry at Wolfram MathWorld - Opens in a new window
An extensive, encyclopedia-style resource including definitions and explanations of trigonometry concepts and terms.