I bough wooden logs (not the chocks, sorry) and want to check the total volume of wood (m³).

I measured top perimeter length (circumference), bottom perimeter length and length of the even log.

[![enter image description here](https://i.stack.imgur.com/eyRA0.jpg)](https://i.stack.imgur.com/eyRA0.jpg)

The log section isn't always looks like a perfect circle, sometimes it's have an oval shape or a complex shape, but never curved inside.

So i have a three numbers in cm: 67, 68, 38.
I entered all the data to spreadsheet and stuck with the right formula.

**What the formula to find the volume of the even log?**

Thank you.