An interactive applet and associated web page that provide step-by-step animated instructions on how to construct a perpendicular to a given line at a given point on the line. 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 a perpendicular at the endpoint of a ray using only a compass and straightedge. 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 animated instructions on how to construct a perpendicular to a given line through a given point off the line. 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 demonstrate the concept of 'perpendicular'. The applet presents two intersecting line segments, one initially at right angles to the other. As you drag the end points of the line segments a message and the right-angle mark at the intersection tell if it is currently perpendicular. The goal is to show what a right angle 'looks like'. 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 perpendicular bisector of a line segment. The applet shows a fixed line and another moveable one that bisects it. As you drag either end of it, it is seen that only when they are perpendicular to each other is the definition valid. 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 show how to determine of one line is perpendicular to another in coordinate geometry. The principle used is that if two lines a re perpendicular to each other the slope of one is the negative reciprocal of the other. The applet shows to lines that the user can move. The slopes are continuously calculated as you drag them, and if the they are parallel they change color. The calculation is shown on screen updated continuously as you drag. The grid, axis pointers and coordinates can be turned on and off. The calculation display can be turned off to permit class exercises and then turned back on the verify the answers. The applet can be printed as it appears on the screen to make handouts. The web page has a full description of the concept of perpendicularity, a worked example and has links to other pages relating to coordinate geometry. 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.

One of the exciting challenges for engineers is the idea of exploration. This lesson looks more closely at Spaceman Rohan, Spacewoman Tess, their daughter Maya, and their challenges with getting to space, setting up satellites, and exploring uncharted waters via a canoe. This lesson reinforces rockets as a vehicle that helps us explore outside the Earth's atmosphere (i.e., to move without air) by using the principles of Newton's third law of motion. Also, the ideas of thrust, control and weight all principles that engineers deal with when building a rocket are introduced.