Hello,
Say the area of the lawn is
, and the area of the path is
. We are given the dimensions of the lawn, so
.
Now you know that
.
Let us define a function that gives the area of the concrete path with respect to some width, denoted
. After investigation, we find that this function is defined by :
. You are trying to find
such as
. Solve
for
:
Using the quadratic formula :
A width can only be positive, so discard the negative solution. You just found the width of the concrete path
Does that make sense ?