> **Q**. Does every (perhaps smooth) compact convex body $K$ in $\mathbb{R}^d$ admit a circumscribing simplex, each facet of which touches (shares a point with) $K$? How about a circumscribing *regular* simplex? This question is inspired by this result (in a paper I have yet to access): > Shizuo Kakutani. "A proof that there exists a circumscribing cube around any bounded closed convex set in $\mathbb{R}^3$." *Ann. Math.*, 43(4):739–741, 1942. Perhaps the regular simplex question is answered already in $\mathbb{R}^2$? If so, I would appreciate a reference. Thanks! <hr /> ![EqTriCircum][1] <hr /> [1]: https://i.sstatic.net/pYXYu.jpg