Complex numbers - animated definition The letter i - math word definition Imaginary-number The letter j - math word definition Icosahedron - A regular polyhedron with 20 faces - One of the platonic solids Platonic solid Identity Trigonometry identities Complex numbers - animated definition The letter i - math word definition The letter j - math word definition Number Real-number Imaginary-number Calculus - Improper Integrals How to construct the incenter of a triangle with compass and straightedge How to construct (draw) the incircle of a triangle with compass and straightedge or ruler Incenter coordinates of a triangle with calculator (Coordinate Geometry) Incenter Incenter of a regular polygon Triangle Centers Overview Triangle incenter, description and properties Triangle incircle definition Incircle of a triangle How to construct the incenter of a triangle with compass and straightedge How to construct (draw) the incircle of a triangle with compass and straightedge or ruler Incircle Incenter of a regular polygon Incircle of a Polygon Triangle incircle definition Included angle definition Triangle given two angles and the included side (ASA) Included - math word definition Included side definition Area of a triangle (Side-angle-side method) with calculator Inequality (opposite of equation) Triangle inequality theorem- Math Open Reference Triangle inequality theorem converse Initial side - math word definition - Trigonometry Inradius Incircle of a Polygon Triangle incircle definition Arc Peripheral Angle Incircle of a triangle Inscribed angle of a circle How to construct an equilateral triangle inscribed in a given circle with compass and straightedge or ruler How to construct a regular hexagon inscribed in a circle with compass and straightedge or ruler Constructing a regular pentagon inscribed in a circle How to construct a square inscribed in a circle with compass and straightedge or ruler Inscribed - math word definition Parallelogram inscribed in a quadrilateral Inscribed (cyclic) quadrilateral Area of an inscribed quadrilateral Diagonals of an inscribed quadrilateral Angle inscribed in a semicircle Square inscribed in a circle Triangle incircle definition Calculus - Instantaneous Velocity Integer Number Calculus - Functions defined using integrals Calculus - Improper Integrals Calculus - Integral Test Calculus - Properties of Definite Integrals Calculus - Polar Area Calculus - Riemann Sums Calculus - Integration By Substitution Intercepted arc Equation of a line - slope and intercept form. (Coordinate Geometry) Intercept (b) of a line (Coordinate Geometry) Introduction to Lines in Coordinate Geometry Interior of an angle definition Alternate Interior Angles definition Interior Angles of a transversal definition Interior - math word definition Interior / exterior angles of a polygon Polygon Interior Angles Interior angles of an inscribed quadrilateral Triangle interior angles definition Calculus - Intermediate Value Theorem Intersecting Chord Theorem Intersecting lines. (Coordinate Geometry) Intersection - math word definition Intersecting Secant Angles Theorem Intersecting Secant Theorem Number The trigonometry arccos() function - inverse cosine - math word definition The trigonometry arcsin() function - inverse sine - math word definition The trigonometry arctan() function - inverse tangent - math word definition Calculus - Invertible Functions The inverse trigonometry functions Irrational number - math word definition Number Irregular polygon - math word definition Area of an Irregular Polygon How to construct an isosceles triangle given base and one side How to construct (draw) an isosceles triangle given base and altitude with compass and straightedge or ruler Construct an isosceles triangle with given leg and apex angle with compass and straightedge or ruler Isosceles triangle - math word definition Calculus - Intermediate Value Theorem