Hi could someone help me out? It would mean a lot to me.
In quadrilateral BCED, we have BD = 11, BC = 9, and CE = 2. Sides BD and CE are extended past B and C, respectively, to meet at point A. If AC = 8 and AB = 5, then what is DE?
By simiilar trianlges, DE = 16.
Use the cosine rule twice.
First in the triangle ABC to calculate the angle at A. (I got cos(A) = 1/10).
Second in the triangle ADE to calculate DE.
I got DE = 18, but that should be checked.