In the diagram, ABC ∼ ACD. If AD = 12 and DB = 15, what is AC? I got it wrong on my test and I don't know how to solve it :(
By Similar Triangles, AC = 12*sqrt(2).
Since △ABC ~ △ACD,
AC / AD = AB / AC
x / 12 = 27 / x
x * x / 12 = 27
x * x = 27 * 12
x2 = 324
x = sqrt(324)
x = 18
? / 12 = 27 / ?
? = √324
? = 18
