right angle 125 videos

Alternate Exterior Angles
Geometry Reasoning, Diagonals, Angles and Parallel Lines
How to define alternate exterior angles and their special properties.
parallel lines angles congruence exterior transversal 
Triangle Angle Sum
Geometry Triangles
How to apply the triangle angle sum theorem.
triangle angle sum theorem 180 degrees 
The Angle Between Vectors
Precalculus Vectors and Parametric Equations
How to compute the angle between two vectors.
dot product angle between vectors position vectors 
Polygon Angle Sum
Geometry Polygons
How to derive the formula to find the sum of angles in any polygon.
triangle angle sum diagonal polygon 
Adjacent Angles
Geometry Reasoning, Diagonals, Angles and Parallel Lines
How to define adjacent angles.
vertex side coplanar 
Using a Protractor
Geometry Geometry Building Blocks
How to use a protractor to measure an angle.
protractor angle acute obtuse right 
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 
The HalfAngle Identities
Precalculus Advanced Trigonometry
How to use the power reduction formulas to derive the halfangle formulas.
the power reduction formulas the half angle formulas quadrants 
The HalfAngle Identities
Trigonometry Advanced Trigonometry
How to use the power reduction formulas to derive the halfangle formulas.
the power reduction formulas the half angle formulas quadrants 
The DoubleAngle Formulas
Precalculus Advanced Trigonometry
How to use the sine and cosine addition formulas to prove the doubleangle formulas.
the sine of a sum formula the cosine of a sum formula the sine double angle formula the cosine double angle formula 
The DoubleAngle Formulas
Trigonometry Advanced Trigonometry
How to use the sine and cosine addition formulas to prove the doubleangle formulas.
the sine of a sum formula the cosine of a sum formula the sine double angle formula the cosine double angle formula 
Vertical Angles
Geometry Reasoning, Diagonals, Angles and Parallel Lines
How to define and identify vertical angles.
vertex intersecting lines congruent 
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 
Other Forms of the Cosine DoubleAngle Formula
Precalculus Advanced Trigonometry
How to derive two more cosine doubleangle formulas.
the Pythagorean identity the cosine double angle formulas 
Other Forms of the Cosine DoubleAngle Formula
Trigonometry Advanced Trigonometry
How to derive two more cosine doubleangle formulas.
the Pythagorean identity the cosine double angle formulas 
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 
Inverse Trigonometric Functions
Geometry Basic Trigonometry
How to use inverse trig functions to find angles in right triangles.
trigonometry right triangle inverse sine cosine tangent