Triangles

Progress
Triangle types
Triangle angles
Triangle inequality theorem
Perpendicular bisectors
Angle bisectors
Medians & centroids
Altitudes
Bringing it all together
Unit test
10 questions
1Take the unit test to identify your areas for growth.
2Review the recommended lessons.
3Test yourself again to show your growth.
Lessons
Triangle typesTriangle anglesTriangle inequality theoremPerpendicular bisectorsAngle bisectorsMedians & centroidsAltitudesBringing it all togetherUnit test
Triangle types
Learn
Classifying triangles
Classifying triangles by angles
Worked example: Classifying triangles
Types of triangles review
Practice
Identify triangles by angles
86%
Completed
Identify triangles by side lengths
100%
Completed
Triangle angles
Learn
Angles in a triangle sum to 180° proof
Triangle exterior angle example
Worked example: Triangle angles (intersecting lines)
Worked example: Triangle angles (diagram)
Triangle angle challenge problem
Triangle angle challenge problem 2
Triangle angles review
Practice
Find angles in triangles
7 questions
Completed
Find angles in isosceles triangles
100%
Completed
Finding angle measures between intersecting lines
100%
Completed
Finding angle measures using triangles
7 questions
Completed
Triangle inequality theorem
Learn
Triangle inequality theorem
Practice
Triangle side length rules
50%
Completed
Perpendicular bisectors
Learn
Circumcenter of a triangle
Circumcenter of a right triangle
Three points defining a circle
Area circumradius formula proof
2003 AIME II problem 7
Angle bisectors
Learn
Distance between a point & line
Incenter and incircles of a triangle
Inradius, perimeter, & area
Medians & centroids
Learn
Triangle medians & centroids
Triangle medians and centroids (2D proof)
Dividing triangles with medians
Exploring medial triangles
Centroid & median proof
Median, centroid example
Altitudes
Learn
Proof: Triangle altitudes are concurrent (orthocenter)
Common orthocenter and centroid
Bringing it all together
Learn
Review of triangle properties
Euler line
Euler's line proof
Unit test
Test your understanding of Triangles with these 10 questions.

It takes about 14 to 18 minutes to finish this test.