Other
Allmath: Math Glossary
Are your students having difficulty understanding math terminology? Try this A-Z glossary on math related terms. It's quick, easy to read, and very complete.
Clark University
Clark University: Dave's Short Trig Course
This Clark University trigonometry tutorial site features questions and answers about what students can learn from trigonometry.
Texas Instruments
Texas Instruments: The Tangent Ratio
In this activity students explore the tangent ratio. Students construct a right triangle using perpendicular lines, and a line that forms the hypotenuse of the triangle. When students construct the hypotenuse line it is very important...
Texas Instruments
Texas Instruments: Walking the Fence Line, Then the Hypotenuse
In this activity, students use the Geoboard to determine the length of the hypotenuse of a right triangles. [Requires Adobe Reader.]
Texas Instruments
Texas Instruments: Surround and Be Found! Triangular Areas, That Is!
In this activity, students use the Geoboard to determine the area of triangles using the surrounding rectangle technique. They also develop and use formulas to determine the area of triangles. [Requires Adobe Reader.]
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: Exploring the Centroid of a Triangle
In this activity, students investigate what happens when all three medians of a triangle are drawn. They learn how to locate the centroid. [Requires Adobe Reader.]
Texas Instruments
Texas Instruments: The Simson Line
Students study the Simson line and analyze the relationship it shares with its triangle. [Requires Adobe Reader.]
Texas Instruments
Texas Instruments: Properties of the Centers of a Triangle
Students investigate the sum of the measures of the interior angles of a triangle. This activity explores interior angles, and their relationship with the exterior angles of a triangle [Requires Adobe Reader.]
Texas Instruments
Texas Instruments: Math Today Dangerous Births
In this activity, using the USA TODAY Snapshot "Dangerous births" students will explore the geometric relationships of triangles using perpendicular bisectors of the sides, bisectors of the angles and medians of the triangle. They will...
Texas Instruments
Texas Instruments: Investigating Lengths of Segments in a Triangle
In this activity, students connect the midpoints of two sides of a triangle, to draw the midsegment of the triangle. They investigate how the length of this segment relates to the third side of the triangle. [Requires Adobe Reader.]
Texas Instruments
Texas Instruments: Math Today Ballooning Inside the Box
In this activity Using the USATODAY infograph, "Ballooning inside the box", students will explore geometric relationships using similar triangles. Identifying triangles with two pairs of congruent angles to explore similarity properties...
Texas Instruments
Texas Instruments: Try Angle?
In this activity, students investigate properties of triangles by randomly generating possible side lengths for triangles. They learn to determine if three line segments can form a triangle. They also learn to classify triangles as...
Texas Instruments
Texas Instruments: Investigating Special Trangles
This activity will help students visualize the construction of these special triangles and find the ratios of the sides. It will help students later when they being trigonometry. [Requires Adobe Reader.]
Math Planet
Math Planet: Algebra 2: Cosines
Defines and explores the law of cosines through examples and a video lesson. [1:41]
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: Triangulos
In Spanish. This interactive activity shows how to compute the area of a triangle and the concept of altitude, median and angle bisector. [Requires Java.]
Writing Fix
Writing Fix: Useful Shapes: Analytical Writing in Primary Math Classrooms
In this lesson, the book entitled The Greedy Triangle, written by Marilyn Burns, is shared. After sharing this read-aloud book, students will illustrate pictures that incorporate the triangle. Then will write three reasons why a triangle...
Shodor Education Foundation
Shodor Interactivate: Triangle Explorer
This applet gives you practice finding the area of a triangle. Great place for students to "discover" how you find the area of a triangle. Directions are just a click away. [Requires Java.]
Sophia Learning
Sophia: Triangle Exterior Angles Practice: Lesson 5
This lesson provides practice problems that apply the triangle exterior angles theorem. It is 5 of 6 in the series titled "Triangle Exterior Angles Practice."
Illustrative Mathematics
Illustrative Mathematics: 6.g Same Base and Height, Variation 2
This is the second version of a task asking students to find the areas of triangles that have the same base and height. This presentation is more abstract as students are not using physical models. They still determine the area of each...
Mangahigh
Mangahigh: Shape: Types of Triangle
Test your knowledge of triangles by identifying the different types.
CK-12 Foundation
Ck 12: Trigonometry: Angle Angle Side Triangles
[Free Registration/Login may be required to access all resource tools.] Find the unknown side of a triangle when two angles and a side are known.
CK-12 Foundation
Ck 12: Trigonometry: Identify Accurate Drawings of Triangles
[Free Registration/Login may be required to access all resource tools.] Determine if diagrams of triangles are accurately drawn.
Khan Academy
Khan Academy: Name Shapes 1
Practice identifying circles, triangles, squares, and rectangles. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.