**The Postal-Scale Function**

**In an Algebra 2
book, Shelby, Katy, and Don found the problem of finding the function which describes
the cost of sending a letter by USPS 1st
class mail. Don found the
scale which he uses, shown below. Katy made a table**

weight (oz) 0-1 1-2 2-3 3-4

cost($) .39 .63 .87 1.11

**The interesting thing is that any # of
ounces between 0-1, including 1, the cost is $.39; between 1-2 ounces, the cost
is $.63. They discovered that after $.39 for 1 ounce, the cost goes up the
same, $.24. So if the weight was 1.25 ounces or 1.8 ounces, the cost would
be the same, $.63. ****In the book
"Mathematica 5" by Stephen Wolfram, Don found the name of this
function, the ceiling function****.
The ceiling of x is written as .**

**Shelby and Katy made the graph and
wrote the equation.**

**The graph of the USPS cost
($) vs. weight (oz) of a letter**

**Great job, Katy and
Shelby!!!**

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