An interactive applet and associated web page that provide step-by-step instructions on how to find a median of a triangle using only a compass and straightedge. The method used involves bisecting one side, then drawing a line from this midpoint to the opposite vertex. The animation can be run either continuously like a video, or single stepped to allow classroom discussion and thought between steps. 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 provide step-by-step instructions on how to construct the orthocenter of a triangle using only a compass and straightedge. The method used involves constructing two altitudes of the triangle, which intersect at the orthocenter. The animation can be run either continuously like a video, or single stepped to allow classroom discussion and thought between steps. 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.

The construction of the perpendicular bisector of a line segment is one of the most common in plane geometry and it is undertaken here. In addition to giving students a chance to work with straightedge and compass, the problem uses triangle congruence both to show that the constructed line is perpendicular to AB and to show that it bisects AB.

This example explains how contour mapping teaches both estimation and spatial visualization skills. To have experience visualizing 3-dimensional fields from a 2-dimensional map helps students throughout their mathematical career. This resource is from PUMAS - Practical Uses of Math and Science - a collection of brief examples created by scientists and engineers showing how math and science topics taught in K-12 classes have real world applications.

This task is for instruction purposes. Part (b) is subtle and the solution presented here uses a "dynamic" view of triangles with two side lengths fixed. This helps pave the way toward what students will see later in trigonometry but some guidance will likely be needed in order to get students started on this path.

This short video and interactive assessment activity is designed to teach second graders about conversion word problems (english units).

This short video and interactive assessment activity is designed to teach fourth graders about conversion word problems (english units).

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

This short video and interactive assessment activity is designed to teach second graders about converting coins - two units.

This short video and interactive assessment activity is designed to teach fourth graders about converting pints to cups.

This short video and interactive assessment activity is designed to teach fourth graders about converting gallons to cups.

This short video and interactive assessment activity is designed to teach fourth graders about converting large units to small units (english units).

This short video and interactive assessment activity is designed to teach fourth graders about converting quarts and cups by pictures.

This short video and interactive assessment activity is designed to give fourth graders an overview of conversion between gallons, pints and quarts.

This short video and interactive assessment activity is designed to teach fourth graders about converting between kiloliters and liters.

This short video and interactive assessment activity is designed to give fourth graders an overview of compound unit capacity (metric units).

This short video and interactive assessment activity is designed to teach fourth graders about converting gallons to pints.

This short video and interactive assessment activity is designed to teach fourth graders about converting pints and quarts by pictures.

This short video and interactive assessment activity is designed to teach second graders about turning words into numbers using a place value diagram.

This short video and interactive assessment activity is designed to teach fourth graders about identifyinging numbers based on statements involving place value.