CK-12 Foundation
Ck 12: Geometry: 30 60 90 Right Triangles Problem Solving
[Free Registration/Login may be required to access all resource tools.] Identify special triangles and use the characteristics of 30-60-90 triangles in problem solving.
CK-12 Foundation
Ck 12: Relationships of Sides in 30 60 90 Right Triangles
[Free Registration/Login may be required to access all resource tools.] Define a 30-60-90 triangle and the relationship between its sides.
Other
Brown Math: A 10 Minute Trig Review
Looking for a 10-minute review of the major concepts of trigonometry? This site is a quick recap of degrees and radians, SOH CAH TOA, Pythagorean identities, and special right triangles are all found here.
OER Commons
Oer Commons: Classifying Triangles
In this lesson, students learn to classify triangles by the size of the angles and the measures of the sides. Students will use interactives to explore equilateral, isosceles, scalene, acute, obtuse, and right triangles. Included are...
Illustrative Mathematics
Illustrative Mathematics: F Tf Special Triangles 1
Using known facts about the unit circle and isosceles triangles together with the Pythagorean Theorem, students can derive the sine and cosine of special angles. Aligns with HSF-TF.A.3.
Illustrative Mathematics
Illustrative Mathematics: F Tf Special Triangles 2
Using known facts about the unit circle and isosceles triangles together with the Pythagorean Theorem, students can derive the sine and cosine of special angles. Aligns with HSF-TF.A.3.
Illustrative Mathematics
Illustrative Mathematics: F Tf Equilateral Triangles and Trigonometric Functions
The purpose of this task is to apply knowledge about triangles to calculate the sine and cosine of 30 and 60 degrees. Aligns with HSF-TF.A.3.
Sophia Learning
Sophia: Two Special Triangles: Lesson 5
This lesson explains what 45-45-90 and 30-60-90 right triangles are and discusses their properties. It is 5 of 5 in the series titled "Two Special Triangles."
Sophia Learning
Sophia: Two Special Triangles: Lesson 1
This lesson explains what 45-45-90 and 30-60-90 right triangles are and discusses their properties. It is 1 of 5 in the series titled "Two Special Triangles."
Sophia Learning
Sophia: Using Right Triangle Trigonometry to Find the Area of Regular Polygons
This lesson will demonstrate how to use right triangle trigonometry and special right triangles (45-45-90 and 30-60-90) to find the area of triangles given the side lengths of the polygon. It is 2 of 4 in the series titled "Using Right...
Sophia Learning
Sophia: Using Right Triangle Trigonometry to Find the Area of Regular Polygons
This lesson will demonstrate how to use right triangle trigonometry and special right triangles (45-45-90 and 30-60-90) to find the area of triangles given the side lengths of the polygon. It is 4 of 4 in the series titled "Using Right...
CK-12 Foundation
Ck 12: Algebra Ii: 4.3 the Unit Circle
Activities in this lesson explore how to identify the coordinates where special right triangles intersect with the unit circle in all four quadrants, use both degrees and radians to identify angles, and explore angles of different sizes...
Curated OER
45 45 90 and 30 60 90 Triangles
The formulas for 45-45-90 and 30-60-90 triangles and the use of the Pythagorean theorem to prove the formulas.
PBS
Pbs American Experience: Triangle Fire
Film and special features on the Triangle Shirtwaist Fire of 1911. Features include a timeline of the deadliest workplace accidents, biographies of famous women of the time, and primary resources of the coverage of the fire. For...
Math Planet
Math Planet: Geometry: Converse of the Pythagorean Theorem and Special Triangles
The converse of the Pythagorean Theorem is examined through examples and a video lesson. [1:04]
Purple Math
Purplemath: Special Angle Values: 30 60 90 and 45 45 90 Triangles
Explains a simple pictorial way to remember basic reference angle values. Provides other memory aids for the values of trigonometric ratios for these "special" angle values, based on 30-60-90 triangles and 45-45-90 triangles.
Mangahigh
Mangahigh: Shape: 3 D Trigonometry
Test your knowledge of determing the lengths and angles of right triangles.
Clark University
Clark University: Dave's Short Trig Course: Tangents and Slopes
Explains what "tangent" is and its role in the right triangle. Slope of a line is investigated and tangent for special common angles is given. Angle of elevation and angle of depression are also covered here.
Wolfram Research
Wolfram Math World: Pythagorean Triple
This site provides extensive information about Pythagorean triples. It begins by explaining its relation to the Pythagorean theorem, and then gives ways to generate Pythagorean triples using relatively prime numbers and Fibonacci numbers.