isosceles triangle 85 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 
Area and Perimeter of Triangles
PreAlgebra Introductory Geometry
Understanding why the area of a triangle is 1/2 base times height

Center and Apothem of Regular Polygons
Geometry Area
How to define the apothem and center of a polygon; how to divide a regular polygon into congruent triangles.
center circumscribed circle inscribed polygon isosceles triangle regular hexagon 
Similar Triangles
PreAlgebra Introductory Geometry
Overview of similarity: congruent angles, proportional corresponding sides

HL
Geometry Triangles
How to use the hypotenuse leg shortcut to determine the congruence of right triangles.
hypotenuse leg triangle congruence right triangles 
Proportional Segments Between Parallel Lines
Geometry Similarity
How to prove two triangles are similar using a line parallel to a base.
parallel lines triangles similar triangles proportion 
Indirect Measurement
Geometry Similarity
How to use similar triangles to measure the height of objects.
indirect measurement similar triangles measurement 
Converse of the Pythagorean Theorem
Geometry Pythagorean Theorem
How to use the converse of the Pythagorean Theorem to determine if a triangle is a right triangle, how to use Pythagorean triples to memorize the lengths of certain right triangles.
right triangle leg hypotenuse converse Pythagorean triples 
Converse of the Pythagorean Theorem
Trigonometry Pythagorean Theorem
How to use the converse of the Pythagorean Theorem to determine if a triangle is a right triangle, how to use Pythagorean triples to memorize the lengths of certain right triangles.
right triangle leg hypotenuse converse Pythagorean triples 
Similarity Shortcuts
Geometry Similarity
How to determine if two triangles are similar using a shortcut.
similar triangles AA SAS SSS proportion congruence 
CPCTC
Geometry Triangles
How to use the principle that corresponding parts of congruent triangles are congruent, or CPCTC.
corresponding parts or congruent triangles proofs 
Vertex and Diagonals
Geometry Geometry Building Blocks
How the vocabulary word vertex applies to different objects in Geometry.
vertex isosceles triangle polygon diagonal cone pyramid prism 
Flowchart Proofs
Geometry Triangles
How to outline a flowchart proof.
flowchart proof given cpctc isosceles triangle reflexive property 
Area of Regular Polygons
Geometry Area
How to derive the formula to calculate the area of a regular polygon.
area apothem side hexagon isosceles triangle perimeter equilateral equiangular 
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 
Inverse Trigonometric Functions
Trigonometry Basic Trigonometry
How to use inverse trig functions to find angles in right triangles.
trigonometry right triangle inverse sine cosine tangent 
Inverse Trigonometric Functions
Precalculus Basic Trigonometry
How to use inverse trig functions to find angles in right triangles.
trigonometry right triangle inverse sine cosine tangent 
Constructing Altitudes
Geometry Constructions
How to define an altitude and draw them on acute, right, and obtuse triangles.
altitudes perpendicular segment vertex opposite side obtuse acute right triangles 
SSS and SAS
Geometry Triangles
How to use the SAS and SSS shortcuts to determine the congruence of two triangles.
triangle congruence side side side side angle side 
ASA and AAS
Geometry Triangles
How to use the ASA and AAS shortcuts to determine the congruence of two triangles.
triangle congruence angle side angle angle angle side