Example Activity – Draw and Measure a Triangle

Use this activity to learn the basics the Cabri™ Jr. App.

1. Press the Œ key and select Cabri™ Jr.
2. Press any key.

3. Create a triangle.
a) Press p to open the F2 menu.
b) Select Triangle.
c) Move the pencil using the| ~ } keys to a location for the first vertex. Press [enter].
d) Move the pencil using the | ~ } keys to a location for the 2nd vertex. Press [enter].
e) Move to a 3rd vertex. Press [enter].
4. Press s to open the F5 menu.

5. Highlight Measure, press the right cursor, and select Angle.

6. Measure one of the interior angles of the triangle.
a) Move the pencil to one of the vertex points. Press [enter].
b) Move the pencil to the vertex of the angle being measured. The vertex point will blink. Press [enter].
c) Move the pencil to the third vertex. Press [enter].

Note: The App will calculate and display the angle measurement near the angle being measured. To drag the numerical measurement to a desired location, use any of the | ~ } keys. Press [enter] when the angle measurement arrives at the desired location.

7. Repeat step 6 to find the angle measurements of the other two interior angles of the triangle.

8. Calculate the sum of the three interior angles.
a) Press s to open the F5 window.
b) Select Calculate.
c) Move the arrow to one of the numerical angle measurements. The number will begin blinking when the angle is selected. Press [enter].
d) Press à key from the keypad.
e) Move the arrow to another angle measurement until it starts blinking. Press [enter].
f) The sum of the two angles selected will be output and you can drag them by using the | ~ } keys. Move the new calculation to a desired location and press [enter].
g) Point to the new calculation until it starts blinking (sum of the 2 angles) and press [enter] to select it.
h) Press the à key.
i) Move the arrow to the measurement for the unselected 3rd angle. Press [enter].
j) The calculation output will represent the sum of all three interior angles. Move the new calculation to a desired location and press [enter].

 

 

 

 

 

9. Press to stop the measurement tool and move the arrow to one of the three triangle vertices. The arrow will become “hollow” to indicate that the vertex being selected.

 

10. Press the ƒ key once, and use any of the |~} keys to drag the vertex to a different location.
Note:When the arrow is near a geometric object, press ƒ to turn the arrow into a hand icon so that you can drag the object.
Notice that the angle measurements change accordingly as the triangle changes shape, but their sum is always the same.