Answer:
See image.
Step-by-step explanation:
Remember if you have a right angle inside of a circle, the hypotenuse is going to land exactly on the diameter. Also, Area of a circle = (pi)r^2 Lastly, remember pythagorean triples such as 3,4,5 or at least, the Pythagorean theorem a^2 + b^2 = c^2
