Any math wizzes out there?

[spedbug]

I scraped through geometery, barely, years ago. SFB isn't getting any help from me. Perhaps one of you nice people can help?

Comments

[myopicmeringue.livejournal.com]

You can also do it by imagining that it was a whole cuboid (20 x 24 x 6) and then take away the missing part ((3 x 10 x 20) + (3 x 4 x 20)/2) from that. I find that way slightly easier, because I find it fiddly to divide the swimming pool into chunks. :-)