We are given a right triangle $\triangle DEF$ with $\angle E = 90^\circ$. We are given $FE = 17$ m and $\angle D = 51^\circ$. We are asked to find the length of $DE$.
Step 2: Use trigonometric ratios
We can use the tangent function, which relates the opposite side and the adjacent side of a right triangle to the angle. In this case, we have $\tan(\angle D) = \frac{EF}{DE}$.
Step 3: Substitute the given values
Substituting the given values, we have
$\tan(51^\circ) = \frac{17}{DE}$.
Step 4: Solve for DE
We can rearrange the equation to solve for $DE$:
$DE = \frac{17}{\tan(51^\circ)}$.
Step 5: Calculate the value
Using a calculator, we find that $\tan(51^\circ) \approx 1.2349$.
$DE = \frac{17}{1.2349} \approx 13.766 \approx 13.8$ m.