In this lesson, learn all about the 30-60-90 triangle. Learn about its sides, its area, and the rules that apply to these triangles. Includes simulations and practice questions.

Dr. Math gives a student a hint on how to prove that an inscribed angle is equal to 1/2 the central angle. You should know what the central angle and inscribed angle are to utilize this site.

The geometry tutorial investigates similar triangles. Students learn about the definitions and theorems of similar triangles. Topics included are angle-angle, side-side-side, and side-angle-side similarity. The activity has several...

The geometry tutorial investigates the definitions and theorems related to inscribed and central angles in circles. An example with a detailed solution is included.

The geometry tutorial investigates congruent triangles. Students learn about the definitions and theorems on congruent triangles. Some topics included are angle-side-angle, side-side-side, and side-angle-side congruence postulates. The...

Use the triangle congruence criteria SSS, SAS, ASA, and AAS to determine that two triangles are congruent. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

As a resource for teachers, an activity of how to connect Venn Diagrams with the five methods of proving triangles congruent - SSS, SAS, ASA, AAS, HL - is explained.

Solve two challenging problems that apply the inscribed angle theorem to find an arc measure or an arc length.

This question and answer site from the Math Forum with Dr. Math presents a problem dealing with the volume of a pyramid. Links are also provided for additional information on related subjects.

This site explains the sum of a simple convergent series using a geometric illustration.

This site from Cut The Knot provides an overview of the law of cosines, complete with an explanation of the law and a proof of the law.

Part one of three; The March 2006 8th grade Math test from the State of New York. The test is 27 multiple choice questions dealing with topics such as algebra (translating into algebraic terms, simplifying expressions, evaluating...

Part two of three; The March 2010 8th grade Math test from the State of New York. The test is six open-response questions covering topics such as geometry (intersecting / parallel lines, Pythagorean Theorem), measurement (maps), and...

Investigate the qualities of a triangle with these seventeen word problems. Many include ways to extend the lesson.

Explore everything about triangles. Learn about the different types, important properties, and how to find its area and perimeter. Check out the solved examples and interactive questions for better understanding.

[Free Registration/Login may be required to access all resource tools.] Students watch a video and attempt practice problems on how to determine a missing angle in a triangle.

[Free Registration/Login may be required to access all resource tools.] Students watch a video and attempt practice problems on finding the missing angles in triangles.

[Free Registration/Login Required] Students explore the concept of finding triangle angle measurement by navigating through the interactive learning module and then answering questions that go along with the module. Students can also...

Reviews the rule that the interior angles of a triangle always add up to 180 degrees. Includes three practice problems.

[Free Registration/Login may be required to access all resource tools.] Students watch a video overview and attempt practice problems on finding a missing angle in a right triangle.

[Free Registration/Login may be required to access all resource tools.] Students watch a video and take an assessment on finding missing angles in composite figures.

[Free Registration/Login may be required to access all resource tools.] Students watch a video and take an assessment on finding missing angles in a polygon.

Find missing angle measures using the properties of triangles. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video, or receive hints.

Review how to derive a general formula for the distance between two points.