Answer: 216/343 or 0.6297
Step-by-step explanation:

To find the pre image you need to back track on the image. To get to the image you used (x-6,y+8). Now you need to use the exact opposite to get back to the pre image. For this you would change the signs to look like (x+6,y-8). Now we just apply this to (-4,1).
(-4+6,1-8)
(2,-7) should be the pre image point.
We have that
point C and point D have y = 0-----------> (the bottom of the trapezoid).
point A and point B have y = 4e ---------- > (the top of the trapezoid)
the y component of midpoint would be halfway between these lines
y = (4e+ 0)/2 = 2e.
<span>the x component of the midpoint of the midsegment would be halfway between the midpoint of AB and the midpoint of CD.
x component of midpoint of AB is (4d + 4f)/2.
x component of midpoint of CD is (4g + 0)/2 = 4g/2.
x component of a point between the two we just found is
[(4d + 4f)/2 + 4g/2]/2 = [(4d + 4f + 4g)/2]/2 = (4d + 4f + 4g)/4 = d + f + g.
</span>therefore
the midpoint of the midsegment is (d + f + g, 2e)