Michael A Scivoletti <[EMAIL PROTECTED]> wrote:
To the math people out there,
Is there a way to create a radius without a ruler? I vaguely
remember seeing this done way back in math class MANY years ago. Don't
the 1 foot to 1 foot lay their curves out using a formular of somekind
that can be used by use 3/16th size folks?
Michael in Northwest Jersey
Ant replies:
Well, yes,
Perhaps what you could really use is a method to fit 3 points to a circle
using only a ruler, a compass and a calculator. First any 3 points whether they
are in a straight line or not are always in a plane. If they are not in a
staight line they are the Vertices of a Triangle. So points A, B, C make a
triangle ABC. Measure the distance between the points. We call distances AB
"c" BC "a" and CA "b" and the 3 angles of your triangle angles A, B, and
C, at the vertices A, B, and C.
Now using the Cosine Rule, cos A = (b^2 + c^2 - a^2) / 2bc, we
calculate angles A and simularly B and C.
Using the Sine Rule we have a/sinA = b/sinB = c/sinC = R and R is the
radius of the circle that incudes all 3 points. Find the centre simply by
drawing arcs with radius R from any 2 of points and checking at the 3rd point
and where they cut is the centre for your circle.
This is use in drilling holes that are not in a straight line, but a
fixed distance from each other. One can use a lathe or a compass to mark out a
circle, centre punch for the first hole, then measure the other 2 distances
with a compass and all 3 holes are on that circle.
What????????
Cheers,
Ant.
[Non-text portions of this message have been removed]
Change your membership, change your message settings, use our CALENDAR, view
shared files or photos, view the list archives, GO TO
http://groups.yahoo.com/group/S-Scale/
Yahoo! Groups Links
---------------------------------
Yahoo! Sports
Rekindle the Rivalries. Sign up for Fantasy Football
[Non-text portions of this message have been removed]
The poll results are in....... To REPLY to the list, use REPLY ALL, to reply
to the sender, use REPLY. I do NOT know if this works on all e-mail software,
but it works on some of the most common ones. For those of you on DIGEST mode,
all REPLY messages go to the list.
Change your membership, change your message settings, use our CALENDAR, view
shared files or photos, view the list archives, GO TO
http://groups.yahoo.com/group/S-Scale/
Yahoo! Groups Links
<*> To visit your group on the web, go to:
http://groups.yahoo.com/group/S-Scale/
<*> To unsubscribe from this group, send an email to:
[EMAIL PROTECTED]
<*> Your use of Yahoo! Groups is subject to:
http://docs.yahoo.com/info/terms/
