the cosine double angle formulas 187 videos

Triangle Side and Angle Inequalities
Geometry Triangles
How to determine the relationship between the side inequalities and angle inequalities in a triangle.
angles smallest to largest sides smallest to largest 
Vertical Angles
Geometry Reasoning, Diagonals, Angles and Parallel Lines
How to define and identify vertical angles.
vertex intersecting lines congruent 
Formulas
PreAlgebra Solving Equations and Inequalities
The importance of solving literal equations for a given variable

Angle Bisectors and Opposite Side Ratios
Geometry Similarity
How to relate the sides of an angle bisected and the lengths of the opposite side.
angle bisector opposite side ratio proportion 
Deriving the Quadratic Formula
Algebra 2 Quadratic Equations and Inequalities
How to derive the quadratic formula by completing the square.
functions domain parent functions inequalities interval notation 
Conic Section Formulas
Algebra 2 Conic Sections
How to identify a conic section by its formula.
parabola circle ellipse hyperbola center focus 
Conic Section Formulas
Precalculus Conic Sections
How to identify a conic section by its formula.
parabola circle ellipse hyperbola center focus 
Constructing an Angle Bisector
Geometry Constructions
How to define and construct an angle bisector.
construction perpendicular equidistant shortest distance to a line bisector 
Central Angles and Intercepted Arcs
Geometry Circles
How to define a central angle and find the measure of its intercepted arc; how to describe the intercepted arcs of congruent chords.
chord central angle intercepted arc arc measure congruent chords side side side shortcut 
The Angle Between Planes
Precalculus Vectors and Parametric Equations
How to find the angle between planes, and how to determine if two planes are parallel or perpendicular.
normal vector the angle between planes perpendicular planes dot product scalar multiple parallel planes 
Change of Base Formula
Algebra 2 Inverse, Exponential and Logarithmic Functions
How to use the change of base formula for logs to evaluate a logarithmic statement.
change of base log logarithm 
Change of Base Formula
Precalculus Exponential and Logarithmic Functions
How to use the change of base formula for logs to evaluate a logarithmic statement.
change of base log logarithm 
Same Side Interior and Same Side Exterior Angles
Geometry Reasoning, Diagonals, Angles and Parallel Lines
How to describe same side interior and same side exterior angles and their special properties.
parallel lines angles congruence interior exterior transversal 
Equation of a Circle
Geometry Pythagorean Theorem
How to derive the equation for a circle using the distance formula.
distance formula radius center circle 
Equation of a Circle
Trigonometry Pythagorean Theorem
How to derive the equation for a circle using the distance formula.
distance formula radius center circle 
Distance Formula
Geometry Pythagorean Theorem
How to derive the equation for the distance between two points using the Pythagorean Theorem.
distance coordinate plane ordered pair segment 
Distance Formula
Trigonometry Pythagorean Theorem
How to derive the equation for the distance between two points using the Pythagorean Theorem.
distance coordinate plane ordered pair segment 
Using a Protractor
Geometry Geometry Building Blocks
How to use a protractor to measure an angle.
protractor angle acute obtuse right 
Applied Linear Equations: Geometry Problem
Precalculus Linear Equations and Inequalities
How to find the angles of a triangle by creating a linear equation.
word problem angle measure 
Applied Linear Equations: Geometry Problem
Algebra 2 Linear Equations
How to find the angles of a triangle by creating a linear equation.
word problem angle measure