Texas Instruments
Texas Instruments: Midsegment of a Triangle
Students explore the properties of triangles formed by connecting the midpoints of two sides of a triangle, and examine the relationship between the two triangles. They study the Triangle Midsegment theorem. [Requires Adobe Reader.]
Texas Instruments
Texas Instruments: Simple Constructions
In this skill activity, students can use the Constructions Tools Menu in Cabri Jr. to contruct a parallelogram. They will also construct an altitude, an angle bisector and a median of a triangle.
Texas Instruments
Texas Instruments: Move Along Little Vertex
In this activity, students use the Geoboard to determine the area of triangles having the same base and same height.
Texas Instruments
Texas Instruments: Triangle Midsegment Theorem
Students can use Cabri Jr. to discover that the midsegment of a triangle is parallel to the third side and half the length of the third side.
Texas Instruments
Texas Instruments: The Orthocenter of a Triangle
Students understand that the orthocenter is the point of concurrence of the three altitudes of a triangle. They construct circumcircles and Feuerbach circles and determine the relationship between them.
Texas Instruments
Texas Instruments: Area of Triangle
This Cabri Geometry activity enables students to review the relationship between the height of a triangle and its perimeter and area.
Analyze Math
Analyze Math: Trapezoid Problems
The geometry tutorial examines the area, length, and vertices of a trapezoid. Topics include Heron's formula. The activity has several examples with detailed solutions.
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: Triangulos Semejantes
Learn how to recognize and construct similar triangles with these interactive activities.
Math Open Reference
Math Open Reference: Similar Polygons and Triangles
A complete reference guide to similar triangles and polygons. It provides definitions and interactive activities that enhance further explanation.
Texas Instruments
Texas Instruments: Exploring the Circumcenter of a Triangle
In this activity, students develop an understanding of the circumcenter of a triangle. Students construct perpendicular bisectors of three sides of a triangle and find the circumcenter.
Texas Instruments
Texas Instruments: Classifying Triangles by the Length of the Sides Using Cabri
This activity uses Cabri Jr. to classify triangles according to the length of their sides. [Requires Adobe Reader.]
Math Planet
Math Planet: Geometry: More About Triangles
Explores triangles and related vocabulary through examples and a video lesson.
Math Planet
Math Planet: Geometry: Triangles: Inequalities
Gain an understanding of how to list the sides of a triangle in order from shortest to longest by viewing examples and a video lesson. [1:01]
Mangahigh
Mangahigh: Shape: Proof of the Sum of the Angles in a Triangle
Determine that all angles in a triangle equal 180 degrees.
Mangahigh
Mangahigh: Shape: Area of a Triangle Using Trigonometry
Teat your knowledge of determing the area of a triangle using trigonometry.
Mangahigh
Mangahigh: Shape: Right Angle in a Semi Circle Rule
Test your knowledge of the measurement of angles in a triangle.
Mangahigh
Mangahigh: Shape: 3 D Trigonometry
Test your knowledge of determing the lengths and angles of right triangles.
Varsity Tutors
Varsity Tutors: Hotmath: Graphing Calculator Practice: Polygons and Area of Plane Figures
Practice using your graphing calculator for measuring and constructing polygons and other plane figures. If you get stumped or if you would like to check your work, then select the View Solution button, which is located directly under...
CK-12 Foundation
Ck 12: Triangle Classification
[Free Registration/Login Required] Students will move the vertices to different points to determine the amount of triangles that can be made. Click learn more to watch a video and click challenge me to answer practice questions.
CK-12 Foundation
Ck 12: Isosceles Triangles
[Free Registration/Login Required] Students are given an Isosceles triangle and are asked to move the point on the line segment to explore how the angle measure changes. Click learn more to watch a video demonstration and click challenge...
CK-12 Foundation
Ck 12: Equilateral Triangles
[Free Registration/Login Required] Students will move point B on the triangle to explore that all sides and angles remain the same. Click learn more to watch a video and click challenge me to answer a practice question.
Merriam-Webster
Merriam Webster: Dictionary Illustration: Incenter
A labeled illustration of an incenter inside a triangle.
Analyze Math
Analyze Math: Medians of Triangle
The properties of the medians of a triangle are explored using an interactive geometry applet.