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.

This applet allows users to study the nature of triangles and their area. It draws random triangles on a Cartesian coordinate system. The user can determine the area of the triangle using his or her preferred method. After the calculated...

Discover the world of "similarity" in this test prep tutorial on similar triangles. Detailed explanation of concept with examples, challenging interactive practice, and a classroom activity that integrates math and science.

This lesson focuses on the properties of triangles, a closed shape that has three sides, three vertices, and and three internal angles. There are different types of triangles such as a right triangle, obtuse, and acute based on the...

Explore the world of the altitude of a triangle in this mini-lesson including its definition, altitudes in different types of triangles, formulae, some solved examples, and a few interactive questions for you to test your understanding.

[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.

[Free Registration/Login may be required to access all resource tools.] Prove two triangles are congruent with the Side-Angle-Side shortcut.

[Free Registration/Login may be required to access all resource tools.] In this lesson students prove two triangles are congruent with the Angle-Side-Angle and Angle-Angle-Side shortcuts. Students examine guided notes, review guided...

Sixth graders apply what they know about area of other polygons to develop a formula for finding the area of a triangle.

Explains the basic concept of similar triangles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.

Explains the basic concept of congruent triangles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.

Apply the property that the longest side of a triangle is opposite the largest angle to solve a few problems.

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

Learn how two triangles are congruent if and only if their corresponding sides and corresponding angles are congruent.

Discover if two triangles are congruent it means that all corresponding angle pairs and all corresponding sides are congruent.

MathWorld goes into detail about equilateral triangles at this site. Use this site to find out how to construct an equilateral triangle using a compass and straight edge. Learn about the altitude of such triangles, and the rationality of...

In each of the following diagrams, two triangles are shaded. Based on the information given about each diagram, decide whether there is enough information to prove that the two triangles are congruent. Aligns with G-CO.B.

In this task, learners must prove that angles and triangles are congruent and that a parallel line passes through the midpoints of two sides of the larger triangle. Aligns with G-SRT.B.4.

Students are shown two triangles touching points on a coordinate grid and are asked to answer questions about their perimeters. The purpose of this task is to apply the Pythagorean theorem to calculate distances and areas. Aligns with...

Given distinct, congruent triangles, students are asked to show that congruence can always be shown with one, two, or three rigid motions. Aligns with G-CO.A.5.

This activity will help learners visualize the construction of congruent triangles and conceptualize properties through measurement and movement of their construction. Students will need access to the TI-84 Plus Family.

Students will use their TI-84 Plus and Cabri Jr to investigate SSS triangle congruence.

The purpose of this task is to apply knowledge about triangles to calculate the sine and cosine of 30 and 60 degrees. Aligns with HSF-TF.A.3.

Given two triangles with some of their angle measures, determine whether the triangles are similar or not.