Which of the following is equivalent to the ratio 3ab: 27ab select all that apply
1: 9
9a: 81a
a: b
a: 3b
2: 18
3b: 27a

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¯¯¯¯¯¯¯¯)?