Help please due today

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 slope of the line that contains the points (-2,1) and (0,-3)

Asix-sided number cube is rolled twice. what is the probability that the first roll is an even numbe and the second roll is a number greater than 4?