Since it is given that 2 side lengths are the same, the 2 triangles produced are similar triangles. That means the ratio from f to g would have to be half, as the ratio of the similar triangle is 1:2.
So what you do it you multiply that number by 100 because it is out of 100% so therefore it would be 140.6%. But I cannot tell you that that is correct without more information.
