can you explain where the 6 and the -5/6 came from? and the 875/3? I have no understanding where it came from and how. and the 1/2r^2 cancelling out the 6r in the denominator.

I would like an in depth explaination. Thank you!

2. [12 points] I have $3500 with which I'd like to build a fence in the shape of a sector, with a partition in the shape of an are running between the midpoints of the straight sides, as shown below. The outside fence costs $5 per foot, and the partition costs $2 per foot. What is the maximum possible total area inside the fence? 5':I $339 -.__ 4 " gr 3 r Are. 1:\" {