Which statement about the solution to the system and its justification is true? Please help!!

Ineed no it anyone can see this

Asource of laser light sends rays ab and ac toward two opposite walls of a hall. the light rays strike the walls at points b and c, as shown below: what is the distance between the walls?

If x varies directly as y, and x = 7.5 when y = 10, find x when y = 4