Curated OER
Area of Right-Angled Triangles
There's a trick to solving the area of a triangle, and it involves a skill your geometers have already mastered. Help them discover the connection between finding a rectangle's area and finding a right triangle's area as they solve for...
Khan Academy
Khan Academy: Right Triangle Word Problems
Solve word problems by modeling real-world (and not-so-real) situations as right triangles and using trigonometry. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Math Is Fun
Math Is Fun: Introduction to Trigonometry
Students are introduced to concepts taught in trigonometry. The tutorial consists of notes and examples.
Oswego City School District
Regents Exam Prep Center: Area of a Triangle and Parallelogram Using Trig
How can trigonometry be used to find the area of a triangle or parallelogram? Does the triangle need to be a right triangle, and how accurate can the results possibly be? The answers to these questions are found here along with several...
Khan Academy
Khan Academy: Special Right Triangles
Use your knowledge of 30-60-90 and 45-45-90 triangles to solve some problems. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Khan Academy
Khan Academy: Solve for an Angle in Right Triangles
Given two sides in a right triangle, find one of the acute angles using trigonometry. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
CK-12 Foundation
Ck 12: Geometry: Pythagorean Theorem and Pythagorean Triples
[Free Registration/Login may be required to access all resource tools.] Apply the Pythagorean Theorem and its converse. Includes videos, exercises, links to interactive activities, etc.
University of British Columbia
University of British Columbia: Proof of the Pythagorean Theorem
A geometric model that proves the Pythagorean Theorem in a step-by-step diagram that students can advance at their own pace. Requires Java.