Khan Academy
Stellar Distance Using Parallax, Cosmology and Astronomy
As a follow-up to the Khan Academy video on parallax, this video focuses on parallax as it relates to astronomical distance. Sal uses cardinal directions and the seasons to help students orient themselves in the proverbial night sky....
Curated OER
How Do You Find the Sine of an Angle in a Right Triangle?
A trigonometric ratio is a ratio between two sides of a right triangle. In this problem, find sin(A) in the given right triangle. Use the ratio of the opposite side over the hypotenuse.
Curated OER
How Do You Find a Missing Side of a Right Triangle Using Cosine?
Trigonometry? What's trigonometry. Well, something to do with triangles, right? Right! Right triangles! In this problem, find the missing length of one of the sides. So set this up as a ratio: cosine(A) = adjacent side length divided by...
Curated OER
How Do You Find a Missing Side of a Right Triangle Using Tangent?
Identify the variables, identify the given values and use a formula to find the missing length in this right triangle problem. What formula? The tangent ratio, which is normally used to show a ratio between two sides of a right triangle,...