Problem with a figure slicing answer

There is a question here: https://brilliant.org/practice/slicing-figures/?p=2 This asks how many shapes of the ones listed can be formed from a slice of a cylinder. The choices are 'ellipse, rectangle, triangle, trapezoid'. The claimed answer is 2, or 'ellipse, rectangle'. However, a rectangle is a member of the trapezoids. Thus there is at least one trapezoid that is a slice of a cylinder, and the correct answer should be 3.

Can someone please point out the flaw here? thanks, chris

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`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
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Comments

Hi, it's using the def'n of a trapezoid as having one pair of parallel sides (but not more). This was implied by listing rectangle separately but I changed the text and put it explicitly, especially since I know some countries don't see the other definition that often if at all.

In the future, if you click the three dots marked "More" below the choices, you can pick "report problem" so it's easier for us to find this kind of issue.

Thanks!

Jason Dyer Staff - 2 years, 11 months ago

Hi Jason, thanks for the clarification and the tip for the future. Chris

Christopher Myatt - 2 years, 11 months ago

Math	Appears as
Remember to wrap math in `\(` ... `\)` or `\[` ... `\]` to ensure proper formatting.
`2 \times 3`	$2 \times 3$
`2^{34}`	$2^{34}$
`a_{i-1}`	$a_{i-1}$
`\frac{2}{3}`	$\frac{2}{3}$
`\sqrt{2}`	$\sqrt{2}$
`\sum_{i=1}^3`	$\sum_{i=1}^3$
`\sin \theta`	$\sin \theta$
`\boxed{123}`	$\boxed{123}$