
Kehley D. answered 06/06/16
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Hi Corrina,
If we say L=length and W=width, we know:
L=W+4
If A is the total area, we also know:
A=190ft2
Now, if we recall that area=length*width, we can say:
A=(L+10)*(W+10)
(note that we had to add 10 to both the length and width because of the grass on both sides of the sandbox - ie. 5+5)
Going back to our first equation, we can substitute W+4 in for L into our third equation, and 190 for A.
190=(W+4+10)*(W+10)
Solve for W to find the width of the sandbox, and then add 4 to find the length.