Answer:
Well, I'm not sure what you mean but Ptolemy's Theorem gives a relationship between the side lengths and the diagonals of a cyclic quadrilateral; it is the equality case of Ptolemy's Inequality. Ptolemy's Theorem frequently shows up as an intermediate step in problems involving inscribed figures.
Answer:
(b) 1:9
(c) 1:8
Step-by-step explanation:
(b) x*y : kx*ky, so 1:k² with k=3 is 1:9
(c) Assuming the rectangles get a z dimension, the volumes would have a ratio of xyz : xkykzk = xyz : xyzk³ = 1 : k³. With k=2 that is 1:8. But the z was never introduced so this is a bit inconclusive.
19% / 100% = ? / 100$ ⇒ the answer is 19 $ :))