Government of Alberta
Learn Alberta: Math Interactives: Exploring Square Roots Video
This video illustrates the concepts of square roots, slope, and the Pythagorean Theorem as they are used in designing and constructing skate park rails, ramps, and pipes. An interactive activity is also included where students are able...
Wolfram Research
Wolfram Math World: Equilateral Triangle
MathWorld goes into detail about equilateral triangles at this site. Use this site to find out how to construct an equilateral triangle using a compass and straight edge. Learn about the altitude of such triangles, and the rationality of...
Texas Instruments
Texas Instruments: Sas Triangle Congruence
This activity will help students visualize the construction of congruent triangles and conceptualize properties through measurement and movement of their construction. Students will need access to the TI-84 Plus Family.
Math Open Reference
Math Open Reference: Congruent Triangles
A complete reference guide to congruent triangles. It provides definitions, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
Texas Instruments
Texas Instruments: Investigate Triangles and Congruence
Students can use the TI-84 Plus family with Cabri Jr. to prove triangle congruence with SSA.
Maths Challenge
Maths challenge.net: Perpendicular Construction
This is a "three star" geometry problem where prior math problem skills and proof experience is recommended to solve this "Perpendicular Construction" problem.
National Council of Teachers of Mathematics
The Math Forum: Geoboard Activities
Math Forum provides a set of links to sites that are related to geoboard activities. There are several great links to lessons using geoboards. The links provide insight into how to use them, including how to perform various measurements...
Math Open Reference
Math Open Reference: Constructions
Learn about drawing shapes using only a compass and straight edge or ruler with out measuring any lengths or angles.
Khan Academy
Khan Academy: Triangle Side Length Rules
Practice solving problems with triangle side length rules.
Oswego City School District
Regents Exam Prep Center: Reference Angles and Triangles
The mathematics session investigates reference angles and triangles. The tutorial consists of class notes, examples, and practice problems with solutions. The teacher resource includes a worksheet on the construction of skateboarding ramps.
Math Aids
Math Aids: Geometry
Great resource to practice and strengthen math skills pertaining to Geometry. Math worksheets are printable, may be customized, and include answer keys.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Constructing the Orthocenter
Dr. Math shows how to construct the orthocenter of any triangle using a compass and straight edge.
Wolfram Research
Wolfram Math World: Right Triangle
This site from MathWorld.com offers extensive information on right triangles. The site contains information on numerous characteristics of right triangles, including constructing similar inscribed triangles, altitudes, Pythagorean...
Illustrative Mathematics
Illustrative Mathematics: G Co Origami Equilateral Triangle
The purpose of this task is to explore reflections in the context of paper folding. Each fold is associated with a line of reflection and understanding each step in the construction requires careful analysis of angles and of the...
Illustrative Mathematics
Illustrative Mathematics: g.c Inscribing a Circle in a Triangle Ii
This task focuses on a fact which comes out of the construction of the inscribed circle in a triangle: the angle bisectors of the three angles of triangle ABC all meet in a point. Aligns with G-C.A.3.
Illustrative Mathematics
Illustrative Mathematics: G Co Inscribing an Equilateral Triangle in a Circle
Suppose we are given a circle of radius r. The goal of this task is to construct an equilateral triangle whose three vertices lie on the circle. Aligns with G-CO.D.13.
Illustrative Mathematics
Illustrative Mathematics: G Co Reflected Triangles
In this task, students must use a straightedge and compass to construct the line across which one triangle was reflected onto another. Aligns with G-CO.A.5 and G-CO.D.12.
Illustrative Mathematics
Illustrative Mathematics: G C Circumcenter of a Triangle
The goal of this task is to construct the circumcenter of a triangle, that is, the point which is the same distance from each of the triangle's three vertices. This task shows that the three perpendicular bisectors of the sides of a...
Math Is Fun
Math Is Fun: Using a Ruler and Drafting Triangle
Students learn how to construct parallel and perpendicular lines. The resource consists of video demonstrations.
University of Cambridge
University of Cambridge: Nrich: Seven Sticks
On this one page website sharpen your logic, triangle properties, and pattern recognition skills while working on this challenge. The solution is available to double check your solution.
Homeschool Math
Homeschool Math: How to Construct an Altitude to a Triangle
Exercises explain how to construct an altitude to a triangle.
Illustrative Mathematics
Illustrative Mathematics: G Srt Folding a Square Into Thirds
The goal of this task is to apply knowledge about similar triangles in order to understand an origami construction: trisection of the side of a square. Aligns with G-SRT.B.5.
Illustrative Mathematics
Illustrative Mathematics: G C Placing a Fire Hydrant
You have been asked to place a fire hydrant so that it is an equal distance from three locations on a map. Students must fold a paper so that this point is where two folds intersect, and they must explain why their construction works and...
Illustrative Mathematics
Illustrative Mathematics: G C Tangent to a Circle From a Point
This task builds on a previous one called ''Right triangles inscribed in circles I.'' Here students are asked to construct a tangent line to a circle from a point outside of the circle. Aligns with G-C.A.4.