Plz help me again with this math stuff -_-

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¯¯¯¯¯¯¯¯)?

Solve this and show you’re work step by step ! -5 3/4+3h< 9 1/4 -

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.