Find out about some common centers of triangles.

See how triangles are congruent where all corresponding angle pairs and sides are the same.

[Free Registration/Login may be required to access all resource tools.] In this lesson students compare sides and angles in triangles. Students examine guided notes, review guided practice, watch instructional videos and attempt practice...

A comprehensive guide for learning all about plane shapes with definitions and solved examples.

[Free Registration/Login may be required to access all resource tools.] Use alternate interior angles to determine angle congruency and the presence of parallel lines.

[Free Registration/Login may be required to access all resource tools.] Prove a quadrilateral is a parallelogram.

MathWorld.com gives a formula for finding distance using the Pythagorean theorem. The formula for finding the distance between two points in Euclidean space is given on this page. The page has links to related topics.

[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to identify whether or not two triangles are similar using AA Similarity.

[Free Registration/Login may be required to access all resource tools.] This concept introduces the HL Triangle Congruence shortcut in order to prove that two right triangles are congruent. Students work on mastering the skill by watch...

[Free Registration/Login may be required to access all resource tools.] In this lesson students prove two right triangles are congruent with the Hypotenuse-Leg shortcut. Students examine guided notes, review guided practice, watch...

[Free Registration/Login may be required to access all resource tools.] Different types of right triangles and trigonometric ratios for special right triangles are covered in this study guide.

The purpose of this task is to lead students through an algebraic approach to a well-known result from classical geometry, namely, that a point X is on the circle of diameter AB whenever angle AXB is a right angle. This consists of...

Proving that an inscribed angle is half of a central angle that subtends the same arc.

[Free Registration/Login may be required to access all resource tools.] Use alternate exterior angles to determine congruency and the presence of parallel lines.

[Free Registration/Login may be required to access all resource tools.] Apply angle bisector properties.

[Free Registration/Login may be required to access all resource tools.] Apply the fact that an angle bisector divides a triangle proportionally.

[Free Registration/Login may be required to access all resource tools.] Apply proportion properties.

[Free Registration/Login may be required to access all resource tools.] Solve problems containing angles outside a circle.

[Free Registration/Login may be required to access all resource tools.] Apply the fact that the altitude of a right triangle creates similar triangles.

[Free Registration/Login may be required to access all resource tools.] Apply the properties of isosceles triangles.

[Free Registration/Login may be required to access all resource tools.] Apply perpendicular bisector properties.

[Free Registration/Login may be required to access all resource tools.] Solve problems containing angles on or inside a circle.

[Free Registration/Login may be required to access all resource tools.] Recognize the sum of the interior angles of a triangle as 180 degrees.

[Free Registration/Login may be required to access all resource tools.] Recognize the sum of the interior angles of a triangle as 180 degrees.