Graph the triangle and the center in a coordinate system.
A'(4,4), B'(4,12), C'(10,4)
Practice makes perfect
We will start by graphing the triangle â–ł ABC in the coordinate system together with the center (4,0), we will call it P.
To scale the triangle with the factor 2 from the center P we must draw lines from P through the vertices of â–ł ABC.
We should now use a compass to get the length between the center and the vertices. We can then use the compass to scale the triangle. Let's start with vertex A.
Since the scale factor is k=2 we should move the compass one time along the line. This will make the distance from the center P twice as long.
Now we found the location for the new vertex A'. To find the other two vertices we will do the same thing. First, measure the distance from center P to the vertices B and C with a compass.
With the scale factor 2 we should move the compass one time along the line. Place the needle at the point, the pencil will then mark the new vertex.
Now that we marked all the new vertices we can form a triangle by drawing lines between them.
With the scale factor 2 we should move the compass one time along the line. Place the needle at the point, the pencil will then mark the new vertex.
The final step is to find the coordinates of the vertices of â–ł A'B'C'. They can be read in the coordinate system.
The coordinate of the vertices of the triangle after dilation is therfore A'(4,4), B'(4,12) and C'(10,4).
