CK-12 Foundation
Ck 12: Geometry: Inscribed Similar Triangles
[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to apply similarity to solve for missing information in inscribed right triangles.
Other
Dans Math: Lessons: Trigonometry
College professor Dan Bach reviews basic trig concepts, including trig functions, right triangles, circles, radians, and polar coordinates. Site includes animated graphs and detailed examples.
PBS
Pbs Learning Media: Triangles: Targeted Math Instruction
Students will learn how to apply the properties and characteristics of all triangles to solve real-world problems and identify and use the unique characteristics of right, isosceles, equilateral, acute, obtuse, and scalene triangles.
University of Saskatchewan (Canada)
University of Saskatchewan: Triangles
This site from the University of Saskatchewan provides an explanation of similar triangles, the Pythagorean theorem, and the distance between arbitrary points in a plane. Example problems for each of these concepts are provided.
Texas Instruments
Texas Instruments: Real Life Real World Activity Forestry
Forest industry professionals make measurements in their work using tools including the Clinometer and the Biltmore Stick. These tools are based on the concepts of similar triangles and trigonometric ratios in a right triangle. This...
Homeschool Math
Homeschool Math: Introduction to Sine
This is an introductory lesson about the trigonometric function sine. Students will study several similar right triangles and the ratio of certain two sides in them.
TeachEngineering
Teach Engineering: You've Got Triangles!
Students learn about trigonometry, geometry and measurements while participating in a hands-on interaction with LEGO MINDSTORMS NXT technology. First they review fundamental geometrical and trigonometric concepts. Then, they estimate the...
Illustrative Mathematics
Illustrative Mathematics: G Srt Defining Trigonometric Ratios
The purpose of this task is to use the notion of similarity to define the sine and cosine of an acute angle. Aligns with G-SRT.C.6.
Mocomi & Anibrain Digital Technologies
Mocomi: Types of Triangles
Explore the different types of triangles and other properties.
National Council of Teachers of Mathematics
Nctm: Illuminations: Tube Viewer Simulation
A computer simulation of viewing through various lengths of tubes at different distances. The simulation also has an exploration of focus questions. [Requires Java.]
Cuemath
Cuemath: Pythagoras Theorem
In this lesson, you will learn about the Pythagoras theorem, its derivations, and equations followed by solved real-world problems on the Pythagoras theorem triangle and squares.
Texas Instruments
Texas Instruments: The Tangent Ratio
In this activity students explore the tangent ratio. Students construct a right triangle using perpendicular lines, and a line that forms the hypotenuse of the triangle. When students construct the hypotenuse line it is very important...
Illustrative Mathematics
Illustrative Mathematics: G Srt, G Mg How Far Is the Horizon?
Some friends are at the beach looking out onto the ocean on a clear day and they wonder how far away the horizon is. A second problem asks how far the horizon would be from the top of a mountain. Students must also answer a question...
Other
Mathematics Internet Library: Free Internet Books
Practice problem worksheets are available for students needing to study basic terms relating to triangles and other math concepts.
Illustrative Mathematics
Illustrative Mathematics: G Srt Mt. Whitney to Death Valley
In this task, students are asked to make a mathematical model and determine if it is possible to see a point on the surface of the Earth that is 85 miles away, and well below sea level, from the top of a mountain. The curvature of the...
National Council of Teachers of Mathematics
Nctm: Figure This: Nctm Math Challenge Three Squares (Pdf)
If you think you can handle the Pythagorean Theorem, then this is a math challenge you should try. Explore geometric relationships and measurement in this one page activity from the NCTM Math Challenges for Families series.