School math, multimedia, and technology tutorials.
This is the second part of the Solving Motion Problems Series, a part of the Math Word Problem Solving Series. In the first part, we have learned that 
In this post, we discuss the two common types of motion problems: two objects traveling to opposite directions and two objects traveling toward each other. » Read more
In Geometry, two objects are congruent if they have the same size and shape. Two triangles drawn on a piece of paper are congruent if we can cut them out with scissors, and superimpose them to fit exactly, that is, without gaps or overlaps. If the triangles fit exactly, the corresponding parts are the parts that coincide. Consequently, corresponding parts of congruent triangles are congruent. Therefore, if two triangles are congruent, then their corresponding angles are congruent and their corresponding sides are also congruent.
In the figure above, if we superimpose the two triangles, 
Math Terms is an iPad App that contains about a thousand entries of middle school and high school mathematical concepts. It is a simple glossary with illustrations that can help students understand mathematical terms and concepts better. I have explored several glossary apps and what separates Math Terms are its practical examples, colorful illustrations, and its intuitive explanations. The image below taken from Math Terms explains Addition Property of Equality.
Math Terms was created by Andy Felong.