Can a system of two linear equations have exactly two solutions?

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¯¯¯¯¯¯¯¯)?

Atriangle with all sides of equal length is a/an triangle. a. right b. scalene c. equilateral d. isosceles

∆red ≅ ∆ by rule will give brainiest if possible