Icosahedron - A regular polyhedron with 20 faces - One of the platonic solids Definition of the math word face Number Prime number - math word definition Definition of "Factor" Definition of "Factor" Ellipse - math word definition- Math Open Reference Foci Foci of an ellipse Parabola definition (focus / directrix form) Focus Foci of an ellipse Elliptical mirrors Finding the foci an ellipse Ellipse - math word definition- Math Open Reference Normal form - math word definition Distance from a point to a line using a formula Area of a triangle given three sides - Heron's Formula with calculator Fraction Numerator Number Reciprocal - math word definition Sine waves- math word definition - Trigonometry Full angle - Math word definition Full Angle - An angle with a measure of 360 deg SOHCAHTOA - math word definition - Trigonometry The sine function - math word definition Graph of the Tangent function - Trigonometry Range of a function The inverse trigonometry functions Graph of the Sine function - Trigonometry Secant function (sec) - Trigonometry Graph of the Cosine function - Trigonometry Introduction to the 6 trigonometry functions Trigonometry function with large and negative angles Functions as used in programming languages Linear function graphical explorer (mx+b) Linear function graphical explorer (ax+b) Graphical Function Explorer grapher (GFE) Graph of a function The trigonometry arccos() function - inverse cosine - math word definition Function Domain Cubic curve and graph display Cosine - math word definition Calculus - Invertible Functions Calculus - Derivative Function Calculus - Functions defined using integrals The trigonometry arctan() function - inverse tangent - math word definition The trigonometry arcsin() function - inverse sine - math word definition The tangent function in right triangles - Trigonometry Calculus - Fundamental Theorem of Calculus