Straight Angle -- from Wolfram MathWorld

A straight angle is an angle equal to 180 degrees=pi radians. Two right angles make a straight angle, and two straight angles make a full angle.

Create an Elliptic Hyperboloid from the matematic formula

Right Triangle -- from Wolfram MathWorld

Angle Trisection: A Math Problem Claimed to Not be Solvable and

Pentaflake, in Google SketchUp - 3DVinci

What Is Trigonometry?

Congruence, Geometry, Transformations & Symmetry

Great circle - Wikipedia

Steinmetz Solid - From Wolfram MathWorld, PDF, Mathematics

Steinmetz Solid - From Wolfram MathWorld, PDF

Philo Line -- from Wolfram MathWorld

Concurrent lines - Wikipedia

Pat'sBlog: 2013

Regular N-gonal Right Antiprism: Application of HCR's Theory of

Generalized Law of Sines -- from Wolfram MathWorld