PLEASE help with these (complex figures)

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¯¯¯¯¯¯¯¯)?

If angle 2=3x +1 and angle 3=2x +4what is angle 2

Bring the fraction a/a-4 to a denominator of 16-a^2