I've been looking at that Chinese math exam problem. [link] I'm having some, well, issues with it. I'm not sure if it's a translation issue or what. Parts i and iii both ask about finding the angle between two lines that, as far as I can tell, don't intersect. Now, for part i, I can sort of finagle the "Show these two lines are perpendicular" into "show that these two lines lie on perpendicular planes," which might be what they're looking for, but it's horribly worded. Part iii, I can only guess that they mean to find the angle between two lines with the slopes that those two segments have, but my answer would really be "the angle between those two lines does not exist."
Part ii, though, looks like an interesting problem. I kind of gave up for now because I can't remember enough analytic geometry.
The British problem, parts i and ii are both from a standard 4th or 5th grade curriculum in the US. Part iii isn't taught until later, but answering it requires nothing other than remembering a definition.
Really, from a "how to write a test" standpoint, I'm not too thrilled with either problem. But I really want to know what they're actually asking in that Chinese one.