How to Make a Unit Circle in GeoGebra

GeoGebra is an extremely useful tool for studying the unit circle as well as the relationship between angles and sides in a right triangle. Follow the instructions below and watch what happens!

Screenshot of GeoGebra showing the unit circle and a 60 degree angle

GeoGebra Instruction 1

1.
Open Algebra View and Graphics View under GeoGebra icon View in GeoGebra icon Menu.
2.
Enter O=(0,0) in Algebra View and press Enter to start your plot.
3.
Select Circle with Center through Point GeoGebra icon on Toolbar, then click O (origin) in Graphics View. Drag the circle until it has a radius of 1 and click on the coordinate system. A point A is now drawn where you clicked.
4.
Select Segment GeoGebra icon from Toolbar and plot the line segment from O (origin) to point A by clicking on the points.
5.
Now you have to draw the line that passes through A and is perpendicular to the x-axis: Select Perpendicular Line GeoGebra icon in Toolbar and draw the normal from A to the x-axis by clicking A first, and then the x-axis. Do the same with A and the y-axis, so that you also get a line that is perpendicular to the y-axis.
6.
Now you need to find intersection points between the lines you made and the axes. Select Intersect GeoGebra icon (it is under the same menu as the Point GeoGebra icon tool). Click the perpendicular line through A, and then click on the x-axis. You can read the x-value in Algebra View. Do the same to find the intersection of the horizontal line and the y-axis.
7.
Select Angle GeoGebra icon, then click the x-axis and the line OA. The angle between the lines is now marked.
8.
Repeat the instructions again, but this time around, select another point on the unit circle. If you want to hide any of the objects that you have drawn, click on the blue dot in the row of the object to what you want to make invisible in Algebra View. You can later click the dot again to make the object visible. If you right-click on the object in Algebra View you can change its properties by clicking Properties. Try it!

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