trapezoidal sums 30 videos

Area of Trapezoids
Geometry Area
How to derive the area of a trapezoid formula using the area of a rectangle.
trapezoid parallelogram base height 
Trapezoid Properties
Geometry Polygons
How to identify a trapezoid and its special properties.
parallel sides isosceles trapezoid base angles base 
Trapezoid Midsegment Properties
Geometry Polygons
How to define the midsegment of a trapezoid, calculate its length, and relate it to a triangle midsegment.
midsegment trapezoid average bases midpoint 
Factoring the Sum or Difference of Cubes
Algebra 2 Factoring
How to factor the sum or difference of cubes.
factoring difference of cubes sum of cubes 
Triangle Angle Sum
Geometry Triangles
How to apply the triangle angle sum theorem.
triangle angle sum theorem 180 degrees 
Trapezoid Arch and Panel Design Problem
Geometry Polygons
How to strategize about solving a problem with trapezoidal arches.
trapezoid arch panel design interior angle equiangular polygon isosceles 
Polygon Angle Sum
Geometry Polygons
How to derive the formula to find the sum of angles in any polygon.
triangle angle sum diagonal polygon 
Sum of Digits
Algebra Word Problems Using Systems of Equations
How to solve a problem when asked to switch the digits of a 2digit number.
sum digits word problem 
Equiangular Polygon Sums
Geometry Polygons
How to find the measure of one angle in any equiangular or regular polygon.
equiangular regular congruent triangles sum 
Geometric Series
Algebra 2 Sequences and Series
How to find the sum of a geometric series.
geometric series sum of a geometric sequence rate infinite sum finite sum 
Geometric Series
Precalculus Sequences and Series
How to find the sum of a geometric series.
geometric series sum of a geometric sequence rate infinite sum finite sum 
Arithmetic Series
Algebra 2 Sequences and Series
How to find the sum of an arithmetic series.
partial sums arithmetic series sum of an arithmetic sequence 
Arithmetic Series
Precalculus Sequences and Series
How to find the sum of an arithmetic series.
partial sums arithmetic series sum of an arithmetic sequence 
The Sine Addition Formulas
Trigonometry Advanced Trigonometry
How to derive the sine of a sum formula.
cosine of a difference formula the cofunction identities the sine of a sum formula 
The Sine Addition Formulas
Precalculus Advanced Trigonometry
How to derive the sine of a sum formula.
cosine of a difference formula the cofunction identities the sine of a sum formula 
Exterior Angles of a Polygon
Geometry Polygons
How to find the sum of the exterior angles in a polygon and find the measure of one exterior angle in an equiangular polygon.
exterior angle sum of angles equiangular polygon 
Factoring Greatest Common Factor
PreAlgebra Polynomials
Factoring is turning a sum or difference into a product

Supplementary and Complementary Angles
Geometry Geometry Building Blocks
How to identify supplementary and complementary angles.
angles sum right angle 
Series and Summation Notation
Algebra 2 Sequences and Series
How to define a series.
series sum of a sequence