Assigning points to coordinates
Introduction of Check Boxes
In GeoGebra, a Check Box is the graphical representation of a Boolean variable. It can either be true or false, which can be set by checking (Boolean variable = true) or unchecking (Boolean variable = false) the checkbox.
Task
Create an applet to drag six points A, B, C, D, E, F and assign them to the correct coordinates which are shown on the right side of the applet by using a Check Box and dynamic texts. In the applet below you can see six points A, B, C, D, E and F. Drag them to the right position and explore the construction.
Explore the construction...
Instructions
| 1. |  | Create the points A, B, C, D, E and F with the Point tool. |
| 2. |  | Hint: Change color and style of the points using the Style Bar. |
| 3. |  | Create six points using random numbers. Enter
RP_1 = (RandomBetween(0, 9), RandomBetween(0, 9))
,
RP_2 = (RandomBetween(0, 9), RandomBetween(0, 9)),
RP_3 = (RandomBetween(0, 9), RandomBetween(0, 9)),
RP_4 = (RandomBetween(0, 9), RandomBetween(0, 9)),
RP_5 = (RandomBetween(0, 9), RandomBetween(0, 9)),
RP_6 = (RandomBetween(0, 9), RandomBetween(0, 9)).
|
| 4. |  | Insert dynamic text1:
A RP_1
B RP_2
C RP_3
D RP_4
E RP_5
F RP_6
Hint: The letters A, B, C, D, E and F should be static text. Then click on Advanced and select tab  Objects. From the list of available objects, select the points RP_1 to RP_6. |
| 5. |  | Move the text to the desired position. |
| 6. |  | You might want to fix the text using the  Settings so it cannot be moved accidentally. |
| 7. |  | Select the Check Box tool and click in the  Graphics View to open the Check Box Dialog. Insert a Check Box with the Caption Help to show / hide the points RP_1, RP_2, RP_3, RP_4, RP_5, RP_6 by selecting them from the drop down menu below the Caption text field.
|
| 8. | | Insert static text2: Right!
Hint: Open the Settings, select tab Position and enter A for the Starting Point.
|
| 9. |  | Open the Settings for text elements using tab Advanced and enter the Condition to Show Object: x(A) ≟ x(RP_1) ∧ y(A) ≟ y(RP_1)
This means, that text2 is only shown if the x- and y-coordinate of A are equal to the coordinates of RP_1.
|
| 10. | | Hint: Activate the  Virtual ABC Keyboard and select to insert logic operators like . |
| 11. | | Repeat Step 8 to 10 with the points B, C, D, E and F. |
| 12. | | Enhance your construction using the Style Bar. |