The sides are triangles. The total number of faces of a pyramid is one more than the number of edges of the base polygon. A prism has two bases and rectangular sides.To find the surface area of a pyramid, find the area of the base and the areas of all the triangular sides and add them together.
A complementary angle are angles that add up to 90 degrees. For example, a 30 degree angle and a 60 degree angle are complementary angles because 30+60=90
You expect to get 12 red marbles out of 60 trials.
So, you expect to get a red marbles 12/60 of the times.
We can simplify that 12/60 to 1/5, which is a choice of answers. :-)
We assume here you correctly assume your probability level when you did your forecast of 12/60. And either you're picking from a small pool and re-insert the marble, or you have a very large amount of marbles (at least 60).