Find the exact solution to each problem. If the exact solution is an irrational number, then also find an approximate decimal solution. See Examples 7 and 8.
Golden Rectangle. One principle used by the ancient Greeks to get shapes that are pleasing to the eye in art and architecture was the Golden Rectangle. If a square is removed from one end of a Golden Rectangle, as shown in the figure, the sides of the remaining rectangle are proportional to the original rectangle. So the length and width of the original rectangle satisfy
$$\frac{L}{W}=\frac{W}{L-W}$$
CAN'T COPY THE FIGURE
If the length of a Golden Rectangle is 10 meters, then what is its width?