Right Triangles and The Unit Circle

Use right triangles for more than just mathematical problems. The first two lessons of a unit ask pupils determine distances between cities by using the Pythagorean Theorem and a map. To cement understanding, learners use trigonometric...

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...

What are all the parts of a right triangle called? What makes it a right triangle? Legs? Triangles have legs? Hypotenuse? Pythagorean Theorem? The instructor diagrams and identifies all the parts of a right triangle for you.

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,...

Given an isosceles triangle, and the value of one angle, find the missing values. There are some special properties about isosceles triangles. Use the triangle sum theorem to solve this problem. Watch this video to see how the instructor...

The triangle sum theorem states that the interior angles of a triangle add up to 180 degrees. So it seems logical that if there are two known values given for the interior angles of a triangle, the third value could be found using this...

Triangles are classified by their angle measurement as well as by the length of their sides. Here are some names that identify the types of triangles: right, isosceles, equilateral, scalene, obtuse, and acute. Watch this video to learn...

While the lesson focuses on right triangles, this activity offers a great way to practice the area of all triangles through an interactive webpage. The activity begins with the class taking a square paper and cutting in in half; can they...

What's a trigonometric ratio? It 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 divided by the hypotenuse to find sin(A). The instructor...

Using the Pythagorean Theorem to solve for missing angles, learners evaluate right triangles and their properties.