AlexTheTrainer wrote:
All I know about geometry in GMAT PS is that “figures are drawn as accurately as possible” (unless otherwise stated, which is rare).
That used to be true in the old days. The test instructions still say that, but if you look at this official GMATPrep question:
https://gmatclub.com/forum/in-the-figur ... 85154.htmlthe diagram is not to scale (and is very misleading), but the question doesn't say the diagram is not to scale. So I'm not sure these days to what extent test takers should trust GMAT PS diagrams (to be fair, that's the only misleading official diagram I've seen, so they're likely trustworthy the vast majority of the time).
It definitely can be useful to estimate answers from diagrams, but because of the question I linked to above, the safest thing to do is to draw the diagrams yourself, and estimate based on what you've drawn. Of course in this particular question, it won't matter at all, since the diagram is clearly to scale (we'd only need to redraw it if the 45 degree angle didn't look like a 45 degree angle). And if we wanted to solve this question properly, a 45 degree angle is 1/8 of a circle (180 is half, 90 is a quarter, 45 is an eighth), so π/2 is one eighth of the circumference, and the circumference is 4π, and since 2πr is the circumference, r = 2.
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