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Khan Academy is a 501(c)(3) nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. Our interactive practice problems, articles, and videos help students succeed in math, biology, chemistry, physics, history, economics, finance, grammar, and many other topics.

Khan Academy provides teachers with data on how their students are doing so they can identify gaps in learning and provide tailored instruction. We also offer free personalized SAT and LSAT practice in partnership with the College Board and the Law School Admission Council.

Our resources have been translated into dozens of languages, and 15 million people around the globe learn on Khan Academy each month.

Ecological succession | Middle school biology | Khan Academy 7:11
Ecological succession | Middle school biology | Khan Academy
Khan Academy
Khan Academy
Disruptions | Middle school biology | Khan Academy 5:27
Disruptions | Middle school biology | Khan Academy
Khan Academy
Khan Academy
Science on Khan Academy 2:43
Science on Khan Academy
Khan Academy
Khan Academy
Constitution Day is in just a few days (Sept 17)! 1:01
Constitution Day is in just a few days (Sept 17)!
Khan Academy
Khan Academy
Khan Academy for Parents 1:10
Khan Academy for Parents
Khan Academy
Khan Academy
📜 Constitution Day is September 17! 0:49
📜 Constitution Day is September 17!
Khan Academy
Khan Academy
Converting polar and rectangular coordinates | Precalculus | Khan Academy 6:02
Converting polar and rectangular coordinates | Precalculus | Khan Academy
Khan Academy
Khan Academy
Applying the rational root theorem | Precalculus | Khan Academy 7:34
Applying the rational root theorem | Precalculus | Khan Academy
Khan Academy
Khan Academy
Graphs of arccos and arcsin | Precalculus | Khan Academy 3:36
Graphs of arccos and arcsin | Precalculus | Khan Academy
Khan Academy
Khan Academy
Identifying reference angles for negative angles in standard position | Precalculus | Khan Academy 3:26
Identifying reference angles for negative angles in standard position | Precalculus | Khan Academy
Khan Academy
Khan Academy
Identifying reference angles of positive angles in standard position | Precalculus | Khan Academy 4:35
Identifying reference angles of positive angles in standard position | Precalculus | Khan Academy
Khan Academy
Khan Academy
Identifying the foci of an ellipse using the radii | Precalculus | Khan Academy 2:29
Identifying the foci of an ellipse using the radii | Precalculus | Khan Academy
Khan Academy
Khan Academy
Interpreting a transformed polynomial function's graph | Precalculus | Khan Academy 3:03
Interpreting a transformed polynomial function's graph | Precalculus | Khan Academy
Khan Academy
Khan Academy
Recursive formula for geometric sequence | Precalculus | Khan Academy 2:17
Recursive formula for geometric sequence | Precalculus | Khan Academy
Khan Academy
Khan Academy
Recursive formula for arithmetic sequence | Precalculus | Khan Academy 3:08
Recursive formula for arithmetic sequence | Precalculus | Khan Academy
Khan Academy
Khan Academy
Using the quotient identities to prove trig identities | Precalculus | Khan Academy 2:01
Using the quotient identities to prove trig identities | Precalculus | Khan Academy
Khan Academy
Khan Academy
Proving the formula for focal length of an ellipse | Precalculus | Khan Academy 3:13
Proving the formula for focal length of an ellipse | Precalculus | Khan Academy
Khan Academy
Khan Academy
Interpreting key features of polynomial graph applications | Precalculus | Khan Academy 2:02
Interpreting key features of polynomial graph applications | Precalculus | Khan Academy
Khan Academy
Khan Academy
Intro to polynomial synthetic division | Precalculus | Khan Academy 4:59
Intro to polynomial synthetic division | Precalculus | Khan Academy
Khan Academy
Khan Academy
Solving polynomial inequalities in factored form | Precalculus | Khan Academy 6:53
Solving polynomial inequalities in factored form | Precalculus | Khan Academy
Khan Academy
Khan Academy
Graphing polar coordinates | Precalculus | Khan Academy 4:05
Graphing polar coordinates | Precalculus | Khan Academy
Khan Academy
Khan Academy
Parametric equations for projectile motion | Precalculus | Khan Academy 9:11
Parametric equations for projectile motion | Precalculus | Khan Academy
Khan Academy
Khan Academy
Solving factored form rational inequalities by testing intervals | Precalculus | Khan Academy 8:01
Solving factored form rational inequalities by testing intervals | Precalculus | Khan Academy
Khan Academy
Khan Academy
Solving rational inequalities from a graph | Precalculus | Khan Academy 1:56
Solving rational inequalities from a graph | Precalculus | Khan Academy
Khan Academy
Khan Academy
Identifying if a ellipse or hyperbola exists from given key features | Precalculus | Khan Academy 5:01
Identifying if a ellipse or hyperbola exists from given key features | Precalculus | Khan Academy
Khan Academy
Khan Academy
Identifying if a parabola exists from given key features | Precalculus | Khan Academy 4:38
Identifying if a parabola exists from given key features | Precalculus | Khan Academy
Khan Academy
Khan Academy
Finding oblique asymptotes of a rational function | Precalculus | Khan Academy 5:15
Finding oblique asymptotes of a rational function | Precalculus | Khan Academy
Khan Academy
Khan Academy
Writing the equation of an ellipse from graph | Precalculus | Khan Academy 3:24
Writing the equation of an ellipse from graph | Precalculus | Khan Academy
Khan Academy
Khan Academy
Estimating an oblique asymptote graphically | Precalculus | Khan Academy 1:48
Estimating an oblique asymptote graphically | Precalculus | Khan Academy
Khan Academy
Khan Academy
Writing transformation form equations of polynomials from a graph | Precalculus | Khan Academy 3:32
Writing transformation form equations of polynomials from a graph | Precalculus | Khan Academy
Khan Academy
Khan Academy
Graph a polynomial with transformations | Precalculus | Khan Academy 4:05
Graph a polynomial with transformations | Precalculus | Khan Academy
Khan Academy
Khan Academy
Solving polynomial functions using their graphs | Precalculus | Khan Academy 3:14
Solving polynomial functions using their graphs | Precalculus | Khan Academy
Khan Academy
Khan Academy
Solving polynomials using a table | Precalculus | Khan Academy 3:22
Solving polynomials using a table | Precalculus | Khan Academy
Khan Academy
Khan Academy
Analyzing horizontal asymptotes of rational functions | Precalculus | Khan Academy 5:50
Analyzing horizontal asymptotes of rational functions | Precalculus | Khan Academy
Khan Academy
Khan Academy
💙 Parents and families, this back-to-school season is for you, too. 1:10
💙 Parents and families, this back-to-school season is for you, too.
Khan Academy
Khan Academy
Finding area-based probabilities | Probability | Geometry (TX TEKS) | Khan Academy 7:58
Finding area-based probabilities | Probability | Geometry (TX TEKS) | Khan Academy
Khan Academy
Khan Academy
Surface area of a rectangular pyramid | Geometry (TX TEKS) | Khan Academy 5:37
Surface area of a rectangular pyramid | Geometry (TX TEKS) | Khan Academy
Khan Academy
Khan Academy
Surface area of an octagonal pyramid | Geometry (TX TEKS) | Khan Academy 7:21
Surface area of an octagonal pyramid | Geometry (TX TEKS) | Khan Academy
Khan Academy
Khan Academy
Surface area of a cone | Geometry (TX TEKS) | Khan Academy 6:15
Surface area of a cone | Geometry (TX TEKS) | Khan Academy
Khan Academy
Khan Academy
🎈🔥 How do hot air balloons float? It’s not magic—it’s thermodynamics! 2:15
🎈🔥 How do hot air balloons float? It’s not magic—it’s thermodynamics!
Khan Academy
Khan Academy
Area between sector and triangle 3:54
Area between sector and triangle
Khan Academy
Khan Academy
Composite area related to circles 2:29
Composite area related to circles
Khan Academy
Khan Academy
Area of regular polygon given radius | Geometry (TX TEKS) | Khan Academy 5:32
Area of regular polygon given radius | Geometry (TX TEKS) | Khan Academy
Khan Academy
Khan Academy
Finding perimeter of shape with arcs | Geometry (TX TEKS) | Khan Academy 4:04
Finding perimeter of shape with arcs | Geometry (TX TEKS) | Khan Academy
Khan Academy
Khan Academy
Finding perimeter of shape with semicircles | Geometry (TX TEKS) | Khan Academy 1:58
Finding perimeter of shape with semicircles | Geometry (TX TEKS) | Khan Academy
Khan Academy
Khan Academy
Area of regular polygon given side length | Geometry (TX TEKS) | Khan Academy 5:44
Area of regular polygon given side length | Geometry (TX TEKS) | Khan Academy
Khan Academy
Khan Academy
Get to know Khan Academy Districts 4:20
Get to know Khan Academy Districts
Khan Academy
Khan Academy
✨ Ready to explore your future? Sign up for our FREE Financial Literacy course! 2:14
✨ Ready to explore your future? Sign up for our FREE Financial Literacy course!
Khan Academy
Khan Academy
College is one path but it’s not the only one 🎯Part 3 is coming up! 1:23
College is one path but it’s not the only one 🎯Part 3 is coming up!
Khan Academy
Khan Academy
“You need to go to college to get a good job.” But is it the only way? Stay tuned for Part 2! 1:30
“You need to go to college to get a good job.” But is it the only way? Stay tuned for Part 2!
Khan Academy
Khan Academy