Answer: 25pi
Explanation: area = piR^2 so 10(radius)^2 = 100pi, only 1/4 of the circle is there so divide the area found (100pi) by 4 to find the one quarter of the circle.
Answer: A
Step-by-step explanation:
Remember that

So if
and
, then we know
.
Then use the Pythagorean identity to solve for cosine:
