• #### Converse of Parallel Lines Theorem - Problem 1

##### Math›Geometry›Reasoning, Diagonals, Angles and Parallel Lines
How to solve for a variable to make lines parallel.
• #### 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 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.
• #### 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.
• #### Isosceles Triangles - Problem 2

##### Math›Geometry›Triangles
How to solve for the measure of the vertex angle of an isosceles triangle given an exterior angle.
• #### ASA and AAS - Problem 2

##### Math›Geometry›Triangles
How to use ASA and AAS and properties of angles formed by a transversal of parallel lines to determine the congruence of vertical triangles and denote the congruence correctly.
• #### Isosceles Triangles - Problem 3

##### Math›Geometry›Triangles
How to solve for a variable used to measure the angles of an isosceles triangle.
• #### Isosceles Triangles - Problem 1

##### Math›Geometry›Triangles
How to solve for the side length and base angle measures of an isosceles triangle.
• #### Parallelogram Properties - Problem 1

##### Math›Geometry›Polygons
How to solve for variables when given the angles of a parallelogram in terms of those variables.
• #### Cyclic Quadrilaterals and Parallel Lines in Circles - Problem 1

##### Math›Geometry›Circles
How to calculate angles in a cyclic quadrilateral given arc measures and two angle measures.
• #### Trapezoid Properties - Problem 1

##### Math›Geometry›Polygons
How to find the measure of all of the angles in an isosceles trapezoid, given one of the upper angles.
• #### Trapezoid Properties - Problem 2

##### Math›Geometry›Polygons
How to find all the angles in an isosceles trapezoid, given one angle.
• #### Kite Properties - Problem 3

##### Math›Geometry›Polygons
How to find the angles in a kite created by the diagonals in terms of a variable.
• #### Kite Properties - Problem 2

##### Math›Geometry›Polygons
How to find the vertex and non-vertex angles in a kite.
• #### Kite Properties - Problem 1

##### Math›Geometry›Polygons
How to find the angles created by the two diagonals in a kite.
• #### The Definitions of Sine and Cosine - Problem 1

##### Math›Precalculus›Trigonometric Functions
How to evaluate sine and cosine when the angle is 0, pi/2, pi, 3*pi/2.
• #### The Definitions of Sine and Cosine - Problem 1

##### Math›Trigonometry›Trigonometric Functions
How to evaluate sine and cosine when the angle is 0, pi/2, pi, 3*pi/2.
• #### Similar Triangles in Circles and Right Triangles - Problem 2

##### Math›Geometry›Similarity
How to find missing side lengths in a right triangle with an altitude drawn from the right angle.