What is the answer to this question?

100 points, hi, i’m not sure how to get the equation from the graph and table.

Arley is building a model of a city map. in one part of the city, three roads form a right triangle, which harley draws as triangle abc, with the following measures: m∠b=90° and m∠a=30°. in his scale model, the hypotenuse of triangle abc, ac¯¯¯¯¯¯¯¯, has a length of 817−−√ cm. what is the value of a (the length of bc¯¯¯¯¯¯¯¯)?

The sales totals at macy's food store have increased exponentially over the months. which of these best shows the sales in the first three months?