Hi, Risrocks. Was it really necessary to post that unnecessarily large image without modifying it first? Please take the time to scale it down and crop out the unnecessary white space.

As for the question, part 1 can be answered by applying the Pythagorean Theorem to the triangle. You will only end up with one unknown, since .

For part 2, use the formula for the area of a circle. A circle of radius has an area of , so a semicircle will have half that area: .