[size=200][b]Draw a circle centred on point "A" that passes through point "B"[/b][/size][br][br][color=#000000]You only need two clicks to draw it. In this activity you will learn to create dynamic texts. A text is an expression closed between double quotes, and has a very interesting property, you can add numbers in the texts.[/color][br][br][color=#9900ff]1st. Activate the "Circle with Centre through Point" tool [icon]/images/ggb/toolbar/mode_circle2.png[/icon].[/color][br][br][color=#9900ff]2nd. Click on two different points in the Graphics View. You will see the centre "A", the point "B" through which it runs and the circle called "c".[/color][br][br][color=#9900ff]3rd. Activate the "Move" tool [icon]/images/ggb/toolbar/mode_move.png[/icon] and type into the Input Bar the command [color=#000000][b]t1=FormulaText("Perimeter =" + Perimeter(c) + "cm")[/b][/color] in order to know the perimeter of the circumference.[/color][br][br][br][br][color=#000000]Texts also have a name in GeoGebra, this is called [color=#000000][b]t1[/b][/color]. The first term, [color=#000000][b]"Perimeter ="[/b][/color], closed into quotation marks, is a static text that indicates the name of the property you want to write. The second term, [color=#000000][b]Perimeter(c)[/b][/color], is dynamic and calculates the property. The third term, [color=#000000][b]"cm"[/b][/color], is also a static text that indicates the unit of measurement.[/color][br][br][color=#000000]Activate the "Move" tool [icon]/images/ggb/toolbar/mode_move.png[/icon] and move the points, you will check how the perimeter of the circle is constantly updated.[/color][br][br][color=#000000]The two curved arrows located in the upper right corner of the Graphics View allow you to reset the activity.[/color][br][br][color=#000000]If the activity is correct, you will get 10 points automatically.[/color]