The Math Forum

Search All of the Math Forum:

Views expressed in these public forums are not endorsed by NCTM or The Math Forum.

Math Forum » Discussions » Education » math-teach

Notice: We are no longer accepting new posts, but the forums will continue to be readable.

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

Advanced Search

Back to Topic List Back to Topic List Jump to Tree View Jump to Tree View   Messages: [ Previous | Next ]
Howard L. Hansen

Posts: 48
Registered: 12/6/04
Re: similar triangles
Posted: Aug 1, 1996 5:46 PM
  Click to see the message monospaced in plain text Plain Text   Click to reply to this topic Reply

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
> Canada

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


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
"Good mathematics is not how many answers you know,
but how you behave when you don't know the answer."

Point your RSS reader here for a feed of the latest messages in this topic.

[Privacy Policy] [Terms of Use]

© The Math Forum at NCTM 1994-2018. All Rights Reserved.