What to pieces of information do you need to notify the equation of a line

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¯¯¯¯¯¯¯¯)?

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)

Reinel saves 30% of every pay check. his paycheck last week was 560$. how much did reniel save last week?