Base on the question where as asking what point would be the center or the rotation if the triangle is rotated 180 degree and the pre image should touch the original image more that ones, base on that, the possible answers would be point D, E and F, if they are in the center of the triangle
It works because 7 x 9 x 10 is the same thing as 7 x 90, since 9 x 10 is just 90. So basically he is just writing more but the answer will still be the same.
