#### Answer

$417.4\ ft$ and $398.2\ ft$

#### Work Step by Step

Step 1. Draw a diagram as shown in the figure.
Step 2. For the left triangle, we have the angle
$B=90^\circ+7^\circ=97^\circ$
Step 3. Using the Law of Cosines, we have
$b^2=(400)^2+(80)^2-2(400)(80)cos97^\circ\approx174,200$
Thus
$b\approx417.4\ ft$
Step 4. For the right triangle, we have the angle
$D=90^\circ-7^\circ=83^\circ$
Step 5. Using the Law of Cosines, we have
$d^2=(400)^2+(80)^2-2(400)(80)cos83^\circ\approx158,600$
Thus
$d\approx398.2\ ft$