Can the area of triangles inside a circle have the same area as the circle

(hurry! ) which expression is equivalent to the following complex fraction?

If the value of cos330°is√3/2 then find cos 165°.

If the altitude is drawn to the hypotenuse of a right triangle, then the two triangles formed are similar to the original triangle and to each other. which set of triangles shows the similar triangles created by the altitude in the diagram?