I need help with number 7 and 9

The general form of the quetion of a circle is ax^2+by^2+cx+dy+e=0 where a=b=0 if the circle has a radius of three units and the center lies on the y axis which set of values of a, b, c, d, and e might correspond to the circle

The surface area of the triangular prism is .

Use the squared identities to simplify sin^2x cos^2x