Making a Square

Square from a side

A square is completely determined if we know a "side". There is a "side" on the drawing pad. Let's make a square!

**First - **click on Goal button to see our goal and** then** click on Reset to start.

Start: Construct the square.

Construct a 90° angle at A.

- Select the 'Angle with given size' icon.

- Click on D and then A. Erase 45 and type in 90. (If you accidently erase the degree sign, you can select if from the left drop-down menu.

Notice that the angle is drawn **and** the point B. By default AB=AD. Let's check.

- Select the 'Circle with given radius' icon. Click on A and then type in 'a' (no quotes) which is the length of AB. Notice that the circle goes through D and B - this means AB=AD. If you want, you can hide the circle by right-clicking on it and deselecting 'Show object'.

- Select the 'Segment between two points' icon and click on A and B.

Now we just repeat ourselves to get the fourth point C of our square.

- Again, select the 'Angle with given size' icon. Click on A and then B. Erase 45 and type in 90. Notice that the angle is drawn and the point C - again by default BC=AB.

- Select the 'Segment between two points' icon and draw line segments BC and CD..

End: Test your construction.

- Select the 'Move' icon and click and drag points A or D. The square will stay a square with side length of AD.

Congratulations on your successful construction!

Authors: LFS - RF, Created with GeoGebra