1. State sales tax is based on retail price. An item that sells for $195.99 has a sales tax of $13.72. Find a mathematic

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1. State sales tax is based on retail price. An item that sellsfor $195.99 has a sales tax of $13.72. Find a mathematical modelthat gives the amount of sales tax y in terms of theretail price x. (Round the coefficient to two decimalplaces.)y =Use the model to find the sales tax on a $550.50 purchase. (Roundyour answer to the nearest cent.)$
2. Find a mathematical model that represents the statement.(Determine the constant of proportionality.)
A varies directly as r2.(A = 9𝜋 when r = 3.)
3. The simple interest on an investment is directly proportionalto the amount of the investment. An investment of $9000 earns$292.50 after 1 year. Find a mathematical model that gives theinterest N after 1 year in terms of the amount investedP.
4. Find a mathematical model for the verbal statement. (Usek for the constant of proportionality.)
V varies inversely as the cube of l.