Math Is Fun Forum

Mathegocart

Member

Registered: 2012-04-29

Posts: 2,226

Silly Triangle Similarity Problem..

I was doing a practice problem..

After drawing an extensive diagram, I found that all triangles were similar. However, the question asks for two triangles that may NOT be similar.
Sorry.. feeling sick.

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Bob

Administrator

Registered: 2010-06-20

Posts: 10,621

Re: Silly Triangle Similarity Problem..

hi Mathegocart

In geometry you always have to be careful not to assume some property just because it looks like it's true.  In that diagram you're not told that BDC = 90 or alternatively that BD is parallel to AE.  If either is true then all the triangles are 30-60-90, but if you shift point D a little along CF then triangle BDC isn't 30-60-90 any longer.

Bob

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Children are not defined by school ...........The Fonz
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