Texas Education Agency
Texas Gateway: Similar Right Triangles: The Altitude to the Hypotenuse
The student will apply and prove the definition of similar triangles and identify and apply the relationships that exist when an altitude is drawn to the hypotenuse of a right triangle, including the geometric mean.
CK-12 Foundation
Ck 12: Geometry: 30 60 90 Right Triangles Intermediate
[Free Registration/Login may be required to access all resource tools.] This concept teaches students about the 30-60-90 special right triangle and how to apply its properties.
Wolfram Research
Wolfram Math World: Right Triangle
This site from MathWorld.com offers extensive information on right triangles. The site contains information on numerous characteristics of right triangles, including constructing similar inscribed triangles, altitudes, Pythagorean...
CK-12 Foundation
Ck 12: Geometry: Inscribed Similar Triangles
[Free Registration/Login may be required to access all resource tools.] Apply the fact that the altitude of a right triangle creates similar triangles.
Government of Alberta
Learn Alberta: Exploring Similarity and Congruence
Begin by watching this captivating video showing how the concepts of similarity and congruence are found in road signs. Following the video [1:27], an interactive applet allows students to resize, flip, move and rotate triangles to...
TeachEngineering
Teach Engineering: Handheld Trigonometry
In addition to understanding the concept of similar right triangles and how they apply to trigonometric ratios, students explore a clinometer app, and discover how it can be used to test the mathematics underpinning trigonometry.
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.
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...
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...
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...
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.