Constructing a proper rectangle is easy when working in GeoGebra. Using perpendicular lines and points, it is easy to create the proper triangle with 90 degree angles and both sets of parallel lines are equal in length.

The above video shows me constructing a rectangle using points and perpendicular lines. I started by putting two points on the space connecting it using a segment. Then I put perpendicular lines on both points. I then selected another point and placed it on the top perpendicular line. After, I put another perpendicular line on the new point and then placed my last point on the intersection of the two lines. As soon as I got my four points, I used the polygon tool to create my rectangle. To clean it up, I removed all the excess lines that I did not need anymore.

This applies to the grade 7 curriculum [u]Shape and Space (3-D Objects and 2-D Shapes)[/u] specifically number 3. Students have to use perpendicular lines to construct geometric shapes.[br]Students need to: [br]- [b]Describe examples of parallel line segments, perpendicular line segments, perpendicular bisectors and angle bisectors in the environment.[/b][br]- Identify line segments on a given diagram that are parallel or perpendicular.[br]- [b]Draw a line segment perpendicular to another line segment, and explain why they are[br]perpendicular.[/b][br]- Draw a line segment parallel to another line segment, and explain why they are parallel.[br]- Draw the bisector of a given angle, using more than one method, and verify that the resulting[br]angles are equal.[br]- Draw the perpendicular bisector of a line segment, using more than one method, and verify the[br]construction.

[u]Grade 7:[br][/u]Give students various geometric shapes and get them to use GeoGebra to construct different shapes. Get them to explain which lines are parallel and perpendicular to other lines.

I like this program for the younger ages when they are just learning how to construct geometric shapes. It is an easy program to use for younger kids so it makes it straightforward. I would use this in my classroom because it is easy for teachers and students to use as well as a good introduction to actually "see" the lines being built.