Explore

Numbers and Quantities

Statistics and Probability

Encyclopedia>Geometry>Planar Figures>Triangles>Triangle Attributes

Triangle Attributes

Concepts Quadrilaterals Triangles

Triangle Attributes The Pythagorean Theorem Concurrent Lines and Collinear Points

Similar Figures The Golden Ratio

Geometric Constructions

Perspective Drawing

What Is a Triangle?
Read here
What Is the Sum of Angles of a Triangle?
Read here
What Is the Formula for the Perimeter of a Triangle?
Read here
What Is the Formula for the Area of a Triangle?
Read here
What Are 30°–60°–90° Triangles?
Read here