What is the area? please help. this would be my last question

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¯¯¯¯¯¯¯¯)?

What is the measure of ac? 5 units 13 units 26 units 39 units 3x- 2b 6x + 9

Select the margin of error that corresponds to the sample mean that corresponds to each population: a population mean of 360, a standard deviation of 4, and a margin of error of 2.5%