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The tools on the C&S toolbar
GeoGebra tool
1. Move (select) - Tool to select object (moving and testing)
Pencil tools
2. New Point – Make a new point
3. Intersection point – Make a point at an intersection of two objects
Straightedge tools
4. Line through two points – Make a line through 2 existing or new points
5. Ray – Make a ray from 2 existing or new points
6. Segment – Make a segment between 2 existing or new points
Compass tools
7.Compass Tool: Circle with radius: distance between 2 points or length of segment and center point
Drawing pad tools
8. Move drawing pad - Shift drawing pad (for bringing objects into the visible window)
9. Zoom out – Make objects smaller (decreases scale of visible window)
10. Zoom in – Make objects bigger (increases scale of visible window)
Labeling tools
11. Angle from 3 points (counter-clockwise from point on leg, vertex, point on other leg)
12. Insert text
Remember: To change the properties of an object you must right-clickor first select it using . Use the undo buttom (top right) to undo your actions.
B. What do we do when it says:Given ...?
1. Given a point C, construct ...
Select New Point tool and click once (anywhere) in the drawing pad. You will get a point A (capital letter).
Right-click on the point and choose Rename. Then type in C and click on Apply.
If you want, hide/show the label C, right-click again on the point and choose Show Label.
To move the point, select the Move tool and click and drag.
2. Given a line m and a point A on m, construct ...
Select Line tool and click once (anywhere) in the drawing pad and then again somewhere else. You will get two (new) points A and B (capital letters) and a line a (small letter) passing through them.
Right-click on the line and choose Rename. Then type in m and click on Apply.
If you want, hide the point B: Right-click on the point and deselect Show Object. DO NOT DELETE it! It is used to define the line. Reccommendation:We suggest that you do not hide B, but just make it smaller and/or just hide its label (see 1.c) to indicate that it is not a given.
To move the line, select the Move tool and click and drag points A or B.
3. Given a line m, construct ...
Follow direction in 2a-c above.
If you want, hide the point A (see 2c). DO NOT DELETE it! It is used to define the line.
Recommendation:We suggest that you do not hide A, but just make it smaller and/or just hide its label.
To move the line, select the Move tool and click and drag points A or B.
4. Given an angle α, construct ...
Select Segment or Ray tool and click once (anywhere) in the drawing pad and then again to the right of this point. You will get 2 points A and B (capital letters) and a segment or ray named a (small letter).
Click again on first point A (make it glow before clicking) and then again and above and right of B. You will get a 3rd point C and a 2nd segment or ray named b.
To label the angle, we use the Angle tool but not as a "tool". Select the Angle tool and click on points B, A, C. You will get an angle named , but by default its value (size) is displayed. Right-click on the angle and choose Properties from the drop down menu.
On the Basics tab, and by "Show label", click on the down arrow and choose "Value".
On the Style tab, click and drag size to 50.
Click on Close.
If you want, hide labels on points and segments/rays.
If you want, hide the 2 non-vertex points. (not recommended).
To move the angle, select the Move tool and click and drag points A, B or C.
5. Given a circle c, construct ...
Select Compass tool compass tool and click once in the drawing pad for center of circle. You will get a point A.
Click again in the drawing pad to determine the radius of the circlue You will get a point B and a circle will show with radius AB.
Move your mouse pointer back to A (the circle will come too) and click on A.
Move and/or Increase/Decrease Radius: Select move tool and then click and drag points A and B.
C. A few more techniques
1. Using the Intersection Point Tool.
You must have two objects that intersect at distinct point on the drawing pad.
You will get one or more new points depending on (1) how many intersection points there are
between the two objects and (2) how you "choose" the intersection point.
Example 1: Draw 2 lines that intersect at a point on the drawing pad.
Select intersect tool. Then, either click on one line and then on the other or click directly on the intersection point (both lines will glow).
Result: 1 new point.
Example 2: Draw a circle and a line through the circle (so two intersection points)
Select intersect tool.
Then click on the line and then on the circle.
Result: 2 new points or
Click directly on a single intersection point (both circle and line will glow)
Result: 1 new point.
2. Using the Compass Tool - the tool that does:
"I need a circle with a radius the distance between A and B andcenter C." or
"Take your compass and stick the needle in point A and widen it until it reaches point B.
Now stick the needle in point C and draw a circle. It will have radius AB."
a. Draw a line segment AB and a point C.
b. Select compass tool and click on A (start radius), then B (end radius) and then C (center point)
Result: A circle with center C and radius the length of line segment AB.
Note: A, B and C do not have to be different points (see B.5 Given a circle …)
3. Undo/Redo /
Many times – particularly when you want to change the properties of a newly created object and forget to change to the move tool – we need to undo our last step. The undo/redo buttons are over at the right of the icon bar.
Note: Sometimes clicking undo once, undoes more than one step. Try clicking redo once.
P.S.This is why we recommend using right-click to change the properties of an object.
4. Forget the order in which you constructed? Look at the Construction Protocol.
Does your teacher want you to write down your steps? And you have forgotten them?
Command: View -> Construction Protocol.
Result: A box with a list of all objects in the order in which they were constructed!
5. Making nice and readable constructs (decorating your objects)
One of the nice things about using GeoGebra to do geometric constructions is that you can change the properties of your objects to make the construction more readable.
You can increase the font-size: Command: Options -> Font-size
We like to make our circles dotted and thinner: Style tab
We also like to color code corresponding objects: Color tab
You can mark congruent angles: Decoration tab
6. Other tips
Shift Construction – Move Drawing Pad: Select Move Drawing pad tool and move your mouse pointer into the drawing pad. Click and drag the drawing pad as desired.
Zooming: Place your cursor in the drawing pad. Use your mouse scroll button.
Remember: Using , you can click and drag any blue point to move it. To move a "not showing" point, first make it visible. You can "get to it" either by opening the algebra window (View -> Algebra Window) or by opening the Properties window (right-click on any object and choose Properties).
Move (select) - Tool to select object (moving and testing)
New Point – Make a new point
Intersection point – Make a point at an intersection of two objects
Line through two points – Make a line through 2 existing or new points
Ray – Make a ray from 2 existing or new points
Segment – Make a segment between 2 existing or new points
Compass Tool: Circle with radius: distance between 2 points or length of segment and center point
Move drawing pad - Shift drawing pad (for bringing objects into the visible window)
Zoom out – Make objects smaller (decreases scale of visible window)
Zoom in – Make objects bigger (increases scale of visible window)
Angle from 3 points (counter-clockwise from point on leg, vertex, point on other leg)
Insert text 
. 
undo buttom (top right) to undo your actions.
New Point tool and click once (anywhere) in the drawing pad.
Move tool and click and drag.
Line tool and click once (anywhere) in the drawing pad and then again somewhere else.
Segment or 
Ray tool and click once (anywhere) in the drawing pad and then again to the right of this point. You will get 2 points A and B (capital letters) and a segment or ray named a (small letter).
Angle tool and click on points B, A, C. You will get an angle named , but by default its value (size) is displayed. Right-click on the angle and choose Properties from the drop down menu.
Compass tool compass tool and click once in the drawing pad for center of circle.
.
intersect tool.
compass tool and click on A (start radius), then B (end radius) and then C (center point)
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