• #### Vertical Angles - Problem 1

##### Math›Geometry›Reasoning, Diagonals, Angles and Parallel Lines
How to find the measure of an angle using the Triangle Angle Sum Theorem and vertical angles.
• #### Number of Handshakes at a Party - Concept

##### Math›Geometry›Reasoning, Diagonals, Angles and Parallel Lines
How to determine the number of handshakes possible in a group of a certain number of people.
• #### Number of Handshakes at a Party - Problem 2

##### Math›Geometry›Reasoning, Diagonals, Angles and Parallel Lines
How to determine the number of people at a party when you know the number of handshakes possible.
• #### Number of Diagonals in a Polygon - Problem 1

##### Math›Geometry›Reasoning, Diagonals, Angles and Parallel Lines
How to determine the number of diagonals in a polygon when you know the number of sides.
• #### Number of Handshakes at a Party - Problem 1

##### Math›Geometry›Reasoning, Diagonals, Angles and Parallel Lines
How to determine the number of handshakes possible when you know the number of people at a party.
• #### Number of Diagonals in a Polygon - Problem 2

##### Math›Geometry›Reasoning, Diagonals, Angles and Parallel Lines
How to determine the number of sides in a polygon when you know the number of diagonals.
• #### Resistor Circuits

##### Science›Physics›Electricity
How resistor circuits incorporate resistors in parallel and in series.
• #### Compositions of Transformations - Problem 1

##### Math›Geometry›Transformations
How to reflect a figure over parallel lines and describe the overall transformation.
• #### Components of a Force - Problem 2

##### Math›Precalculus›Vectors and Parametric Equations
How to find the components of the weight of a block parallel to and perpendicular to the surface of an inclined plane.
• #### The Angle Between Vectors - Problem 2

##### Math›Precalculus›Vectors and Parametric Equations
How to determine whether two vectors are perpendicular or parallel.
• #### The Angle Between Planes - Problem 1

##### Math›Precalculus›Vectors and Parametric Equations
How to determine if two planes are parallel or perpendicular.
• #### Components of a Force - Problem 3

##### Math›Precalculus›Vectors and Parametric Equations
How to use the component of an object's weight parallel to the surface of an inclined plane to find the weight of the object.
• #### Lines in 3D - Problem 2

##### Math›Precalculus›Vectors and Parametric Equations
How to find the vector equation of a line parallel to a given line L that passes through a given point not on L.
• #### The Angle Between Planes - Problem 3

##### Math›Precalculus›Vectors and Parametric Equations
How to find an equation of a plane parallel to or perpendicular to a given plane.
• #### The Angle Between Planes - Concept

##### Math›Precalculus›Vectors and Parametric Equations
How to find the angle between planes, and how to determine if two planes are parallel or perpendicular.
• #### Vector Operations in 3D - Problem 1

##### Math›Precalculus›Vectors and Parametric Equations
How to find the angle between two vectors in 3D, and how to tell whether two vectors are parallel or perpendicular.

• #### Capacitors

##### Science›Physics›Electricity
How capacitors store energy.
• #### Trapezoid Properties - Concept

##### Math›Geometry›Polygons
How to identify a trapezoid and its special properties.
• #### Compositions of Transformations - Problem 3

##### Math›Geometry›Transformations
How to identify the transformation of a reflection across two lines in a coordinate plane.