Which teacher should I ask to help explain the six-year math problem in primary school? It is best to list the ideas and processes to solve the problem. Thank you for your satisfaction with the answer. You can add points! The first thing to know is that logs can be regarded as cylinders.

The calculation formula of cylinder volume is: bottom area × height =πR? ×h

Because its diameter is doubled, its radius is doubled and its length is reduced by half, that is, its height is reduced by half.

So the logarithmic volume at this time is π(2r)? ×h/2=π4r？ × height /2

Compared with the original formula, the front is × 4 and the back is ÷2, so the overall volume of log is × 2.

Corresponding weight ×2

40 kg× 2 = 80 kg

That's it, thank you, hope to adopt!