We are given a 6 cm tall object placed 19 cm away from a mirror with a focal length of 38 cm. First we can find the location of the image, using the mirror formula, which shows the relationship among the focal length of the mirror and the distances of the object and the image away from the mirror:
In this example, f=38cm and Do = 38/2 or 19cm, so
1/38 = 1/19 + 1/Di
1/38 = 2/38 + 1/Di
Di = -38
Then we can use the magnification equation to calculate the magnification of the image:
In this case we know Di and Do, so we will use those:
M = -(-38)/19
M = 2
So your mirror has created an image that is 2X the size of the original object.