A park is 4 times as long as it is wide. If the distance is 12.5 km what is tha area of the park?

This can be taken as a series of equations

L=4W

L=12.5

What is L*W

With this, we can substitute 12.5 into L=4W to get 12.5=4W, so W=3.125

So, L*W=12.5*3.125=39.0625, or about 39 km²