This simulation allows you to observe the behavior of an object reflecting around a circular table.

Checklist for students to use to ensure that all aspects of a constructed response math problem are answered and checked over before completion. 

This collection of videos, animations and documents comes from the NCSSM AP chemistry online course. Chapter nine provides practice and demonstrations related to chemical bonding and geometry.

This task is primarily about volume and surface area, although it also gives students an early look at converting between measurements in scale models and the real objects they correspond to.

An interactive applet and associated web page defining a circle. The applet shows a circle where the user can drag the center and a point on the circle. The radius line supports the definition that all points on the circle are a fixed distance from the center. The web page has the definitions of all the circle-related objects, such as diameter, chord etc, with links for each. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

Reference Sheet for students with definitions and formulas used when looking at circles from a geometric perspective.

This task shows that the three perpendicular bisectors of the sides of a triangle all meet in a point, using the characterization of the perpendicular bisector of a line segment as the set of points equidistant from the two ends of the segment. The point so constructed is called the circumcenter of the triangle.

An interactive applet and associated web page that show the properties of a circumcircle of a polygon. The applet shows a regular polygon where the user can drag the vertices to reshape it and alter the number of sides. As the polygon is being varied, the circumcircle is shown, passing through all vertices. The text describes two ways to calculate the radius of the circumcircle, depending on what you are given to start. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

An interactive applet and associated web page that demonstrate the circumference of a circle. The applet shows a circle with a radius line. The radius endpoints are draggable and the circle is resized accordingly. The formula relating radius to circumference is updated continually as you drag. Introduces the idea of Pi. The formula can be hidden for class discussion and estimation. See also the entries for circumference and diameter. See also entries for radius and diameter. Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

This short video and interactive assessment activity is designed to give fourth graders an overview of angles.

This short video and interactive assessment activity is designed to teach fourth graders about classifying all types of triangles by lengths of sides.

This short video and interactive assessment activity is designed to teach third graders about classifying all types of triangles by lengths of sides.

This short video and interactive assessment activity is designed to teach third graders an overview of triangle classifications.

This short video and interactive assessment activity is designed to teach fourth graders about classifying triangles based on equal sides.

This short video and interactive assessment activity is designed to teach third graders about classifying triangles based on equal sides.

This short video and interactive assessment activity is designed to give fourth graders an overview of triangle classifications.

I would recommned using this task after feeling confident in your students' understanding of the properties of a parallelogram. While it could serve as a review, I think it is best suited as in introductory piece to get students to see how the properties have a trickle down effect to other quadrilaterals.

After introducing the properties of parallelograms to students, this activity is a good introductory piece (with a little creativity). Encourage students to engage with the story and add their own details, as well as highlight the relationships between the special parallelograms. Remixed from: Classifying Special Parallelograms by Mitch Curtis

Accuracy of measurement in navigation depends very much on the situation. If a sailor's target is an island 200 km wide, sailing off center by 10 or 20 km is not a major problem. But, if the island were only 1 km wide, it would be missed if off just the smallest bit. Many of the measurements made while navigating involve angles, and a small error in the angle can translate to a much larger error in position when traveling long distances.

Students must calculate the volume of a cone in this real world task.