Are they similar? The lesson provides an explanation of the angle-angle criterion for triangle similarity. Several problems allow the class to determine whether the two triangles with the given angle measures are similar or not. 

After reviewing characteristics of seven types of triangles, young geometers discover how to find the missing angle of a triangle. Then, they practice identifying triangles, find missing angles, and find missing side lengths of...

Investigate how similar and congruent figures compare. Learners understand congruent figures have congruent sides and angles, but similar figures only have congruent angles — their sides are proportional. After learning the...

An informative lesson contains a brief explanation of how the sum of the angles of a triangle is a line. The lesson continues with determining the missing angle in a triangle, or solving for a variable. Using the sum of the...

Review for the test with a comprehensive list of terms and concepts for the unit on congruence and similarity. It divides divides the sections in the order of the lessons presented during the unit. 

Scholars can use area formulas, but can they apply what they know about area? The lesson challenges learners to think logically while practicing finding area of shapes such as rectangles, circles, parallelograms, triangles, and other...

How many right triangles can you find in a prism, cone, or pyramid? Using right triangles to find lengths in three-dimensional figures is the focus of the lesson. After working with the Pythagorean Theorem to find missing side...

Geometry is full of shapes, figures, and corresponding things here and there. The guide shares all of the key pieces of geometric information in a nicely color-coded and labeled sheet. 

Pupils study angle measurements between different types of angles associated with parallel lines and transversals. The independent practice asks pupils to identify the types of angles in a diagram and to determine the measure of...

[Free Registration/Login may be required to access all resource tools.] An overview of altitudes and geometric mean is provided in this study guide.

Dr. Math responds to a question about how to determine if two triangles are similar. The Dr. goes into detail about the process and gives several examples that are worked out for you.

[Free Registration/Login may be required to access all resource tools.] This study guide looks at similar polygons, scale factor (ratio), and triangle similarity.

Brush up on your math skills relating to similar triangles then try some practice problems to test your understanding.

A complete reference guide to similar triangles and polygons. It provides definitions and interactive activities that enhance further explanation.

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.

Models how to write a similarity statement about different types of triangles and quadrilaterals.

[Free Registration/Login may be required to access all resource tools.] This study guide looks at several examples of self-similarity.

Learn about similar triangles with this helpful reference tool. Provides a detailed definition, examples, and an interactive activity that enhances further explanation. Includes links to related topics.

Looks at the garment factory industry in the 1800s and the early part of the 20th century, where workers toiled in sweatshop conditions. After a terrible fire at the Triangle Shirtwaist Company in 1911, labor unions gained support in...

College professor Dan Bach reviews basic trig concepts, including trig functions, right triangles, circles, radians, and polar coordinates. Site includes animated graphs and detailed examples.

This site defines parallel lines, parallel lines cut by a transverse, and congruent triangles. It also contains links for related terms.

Find the necessary information to decide if triangles are similar at this MathWorld site.

This MathWorld site gives a visual description of dilation and the different kinds of dilation in a similarity transformation.

This site defines eleven theorems relating to parallel lines and similar and congruent triangles. Links to the theorems and relevant term descriptions are provided.