The answer is 248. Working out is in the picture.
One leg is horizontal, on the line y=3. Another leg is vertical, on the line x=1. The point where these intersect, D(1, 3) is the vertex of a right angle. Any right triangle inscribed in a circle has its hypotenuse as the diameter of the circle.
Since the triangle is a right triangle, the circumcenter is the midpoint of the hypotenuse: ((8, 3) + (1, -5))/2 = (4.5, -1).
The pink bar graph is 150
So the formula for this is for every inch of width, you multiply by 2 to get the length.
Here, I made a table for it.
2×2=4
4×2=8
7×2=14
8×2=16 or 16÷2=8
The question is "What's Stella's opportunity cost of working on her serve for an hour?" The rest of the info looks like it's meant to confuse you. They charge $10 an hour. She values an hour of her time at $20. I believe that means she would pay $20. Hope this helps!