Rays are named according to their endpoints, the first one named is the "starting" endpoint, the second one is the one that will continue on into infinity. Therefore, ray BA has a terminal endpoint at B and goes through point A into infinity. Ray AB has a terminal endpoint at A and goes through point B into infinity. Definitely NOT the same ray.
Answer:
2c+10
Step-by-step explanation:
This series converges.



Both component series are geometric with ratios less than 1, so they both converge.


So we have

a quarter of a circle is 19.625
so the area of full circle is 19.625 x 4 = 78.5 sq. km
area of a circle is PI x r^2
78.5 = 3.14 x r^2
78.5/3.14 = 25 = r^2
r = sqrt(25) = 5
radius is 5 km
circumference ( perimeter) = 2 x PI x r
2 x 3.14 x 5 = 31.4 km
perimeter is 31.4 km