Let's assume they meant C=40 degrees. With an angle like that they're asking for approximation; we'll oblige.
The circumradius is the product of the triangle sides divided by four times the area.
Here we have remaining side given by the Law of Cosines.



The area is

The circumradius is
Answer: 13
Step-by-step explanation:
65-13=54
54/4=13
Order of operations
1 serving = 2/3 cup
12 serving = 2/3 x 12 = 8 cups
Answer: 12 servings of muffin would need <u>8 cups</u> of the muffin mix.