Question : Is the following true?
"Letting $K$ be a convex bounded closed set on a plane, then there exists a triangle $M$, which includes $K$, such that $|M|\le 2|K|$. Here, $|M|,|K|$ is the area of $M,K$ respectively."
Motivation : First, I've thought about the case that $K$ is a parallelogram. Then, I reached the above expectation, but I can neither prove this nor find any counterexample. Can anyone help?
Update : I crossposted to MO.
I'm posting an answer just to inform that the question has received an answer by Joseph O'Rourke on MO.
He introduced this page.