## 88. Math Puzzle $9 / 72$

We construct a square with a side length of $10 \mathrm{~cm}$ and on each side, we construct an equilateral triangle outward. Then we fold the four triangles so that the triangle tips meet at one point.

Calculate for this body a) the surface area, b) the height $h$, and c) the volume $V$!
This body is a pyramid with a square base.

a) $O=273 \mathrm{~cm}^{2}$, b) $h=7.1 \mathrm{~cm}$, c) $V=236 \mathrm{~cm}^{3}$