What are some real world examples of slope?

-- a road rises 5-ft for every 100-ft of distance; very difficult to run or bike up the hill

-- gasoline costs $2.75 per gallon; graph of (amount you pump) vs. (your cost) is a straight line
with a slope of 2.75

-- snow falls at the rate of 1.36 inches per hour; graph of (elapsed time since the snow began)
vs. (depth of snow) is a straight line, beginning at the origin, with a slope of 1.36

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