Since F is the midpoint of EG, EF and FG are equal. We know that FG is 4 units, so EF must be 4 units. We also know that FH and EF make EH, so we substitute the values that we have.
Since f is the midpoint of eg, and fg is 4, ef is also 4. Since fh is 6 and fg is 4, gh is 2. Now add ef, fg, and gh to get the length of eh. eh = 4+4+2 = 10.
