Use the alphabet as a tool for teaching your class about geometric figures. Break apart capital letters into line segments and arcs. Classify angles as right, acute, or obtuse. Identify parallel and perpendicular lines. An excellent...

This is an interesting geometry problem. Given the figure, find the area of a triangle that is created by the intersecting lines. The solution requires one to use what he/she knows about coordinate geometry, as well as triangle...

Four is the perfect number—if you're talking about parallelograms. Scholars determine a possible fourth vertex of a parallelogram in the coordinate plane given the coordinates of three vertices. They read a conversation...

While the lesson plan focuses on right triangles, this activity offers a great way to practice the area of all triangles through an interactive webpage. The activity begins with the class taking a square paper and cutting in in half; can...

While it may seem incredibly obvious to the geometry student that congruent sides make congruent triangles, the proving of this by definition actually takes a bit of work. This exercise steps the class through this kind of proof by...

Geometers explore symmetries of isosceles triangles by using rigid transformations of the plane. They complete four tasks, including congruence proofs, which illustrate the relationship between congruence and rigid transformations. The...

An upper-level treatment of what is often presented as a basic concept (the right angle of an inscribed circle on the diameter), this activity really elevates the mathematical thought of the learner! Expected to develop formulas...

After learning that the sum of interior angles for triangles is 108 degrees, take it further to show that the sum of angles in any polygon is the same! Using hexagons, pupils practice finding the measure of the six congruent angles. Make...

Students, teachers, and parents alike will enjoy this challenging math site. It contains a clever brain teaser section plus creative problems related to algebra, geometry, measurement, numbers, statistics, and probability. A Spanish...

In this activity, students will explore the properties of rotations and the relationships between the original and image figures.

Students can use the TI-84 Plus family with Cabri Jr. to segment lengths in a triangle.

Using Cabri Jr. and the properties of rotations to get a true understanding of how a figure is rotated about a point.

Discover how the geometric shape of an object directly relates to its usefullness in this math challenge from the NCTM Math Challenges for Families collection. A one page activity that you can print or download.

Use this rhyming description of Max's Fantastical Zoo to make some amazing animals from geometric shapes. There is a teacher's guide for easy lesson planning.

[Free Registration/Login Required] Students will move the vertices of the quadrilateral to form the congruent quadrilateral. Click learn more to watch a video and click challenge me to answer a practice question.

[Free Registration/Login Required] Students determine whether a hexagon can tessellate or not. Click challenge me to answer practice questions and click learn more to watch a video.

[Free Registration/Login Required] Students determine if squares can tessellate. Click challenge me to answer practice questions and click learn more to watch a video.

[Free Registration/Login Required] Students will explore tessellations and whether a polygon can tessellate. Click challenge me to answer practice questions and click learn more to watch a video.

Create regular and irregular polygons and determine the angles and side lengths with this interactive exercise. Use Safari or Chrome browser.

Sports such as hockey, football, basketball and tennis use balls of different sizes. Can you arrange a selection of different balls in a line each touching the next to make the shortest line? This activity offers opportunities for...

Did you know that two-dimensional shapes are also called polygons? This lesson describes the various 2-D shapes and includes two interactive games to reinforce skills.