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.

A comprehensive list of 2D shapes and 3D solids with everything from a triangle to a dodecahedron. Includes illustrations and short descriptions of attributes for each.

Explore the different types of triangles and other properties.

The goal of this task is to help students synthesize their knowledge of triangles where only two of the vertices have been given. They will need to know that a triangle inscribed in a circle, with a diameter of the circle as one side, is...

Reflect any point, line segment, triangle, or any other figure over one or two lines using this dynamic applet. Points and lines are entered by point-and-click rather than by typing equations or ordered pairs. A very neat exercise to...