linear foot cost.

Question

I have to install a fence and Im trying to calculate the cost of the fence, if the fence costs me 25.00 for an 8 ft panel and I need 40 ft .......  or i need 100 feet.   

Answer 1

this type of problem should be attacked using a proportion--total expense is proportional to the linear length.

$25/8 ft = $ x/40 ft, etc.   solve for x, the cost for 40 ft of fencing.