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Topic: similar triangles
Replies: 2   Last Post: Aug 4, 1996 12:10 PM

 Messages: [ Previous | Next ]
 Howard L. Hansen Posts: 48 Registered: 12/6/04
Re: similar triangles
Posted: Aug 1, 1996 5:46 PM

Tim Doskoch wrote:
>
> We know that if two angles of one triangle are equal to two angles of
> another triangle, then the triangles are similar, and corresponding sides
> have the same ratio.
>
> So if we have two triangles ABC and DEF (labeled clockwise from the apex),
> where angle A = angle D and angle B = angle E then: AB/DE = BC/EF = CA/FD.
>
> Often, somebody will use AB/BC = DE/EF and get the same answer as if they
> used the above ratios.
>
> In what circumstances can you mix up the similar ratios with a correct result?
>
> This also begs the question, in what circumstances will you not get a
> correct result?
>
> Tim Doskoch
> Edmonton, Alberta

Since we may assume BC and EF <> 0, I guess I see the two statements:

AB/DE = BC/EF and AB/BC = DE/EF

as equivalent!

AB/DE = BC/EF --> AB*EF = DE*BC --> AB*EF/BC=DE --> AB/BC = DE/EF

--
Howard L. Hansen
Assistant Professor of Mathematics
Western Illinois University
Macomb, IL 61455
http://www.ECNet.Net/users/mfhlh/wiu/index.htm
"Good mathematics is not how many answers you know,
but how you behave when you don't know the answer."

Date Subject Author
8/1/96 Tim Doskoch
8/1/96 Howard L. Hansen
8/4/96 Tim Doskoch