This fourth-grade geometry lesson teaches the definitions for a line, ray, angle, acute angle, right angle, and obtuse angle. We also study how the size of the angle is ONLY determined by how much it has "opened" as compared to the whole...

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...

How can trigonometry be used to find the area of a triangle or parallelogram? Does the triangle need to be a right triangle, and how accurate can the results possibly be? The answers to these questions are found here along with several...

[Free Registration/Login may be required to access all resource tools.] Learn about the converse of the Pythagorean Theorem and some of its applications. Also explains how to identify acute and obutse triangles through the use of the...

In this interactive website, students practice various math skills such as identifying different types of angles, use the degree symbol, estimate and measure angles, and construct angles.

Learners will learn how to apply the properties and characteristics of all triangles to solve real-world problems and identify and use the unique characteristics of right, isosceles, equilateral, acute, obtuse, and scalene triangles.

Math glossary and terms on angles for kids. Learn the definitions used in this mathematics subject such as acute, obtuse, and right angles on this site.