For you math wizards

Page 1 of 4
• posted on April 15, 2013, 3:14 pm
I need to draw an arc for a piece of trim. The end points of the arc are 5 feet apart and the depth of the arc at the center point is 2 inches. What is the radius of the circle?
There ought to be an equation for this that would be far superior to trial and error, oui?
Larry
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 15, 2013, 3:21 pm
On 4/15/2013 9:14 AM, Gramp's shop wrote:

feet apart and the depth of the arc at the center point is 2 inches. What is the radius of the circle?

<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 15, 2013, 3:25 pm
On 4/15/2013 9:14 AM, Gramp's shop wrote:

feet apart and the depth of the arc at the center point is 2 inches. What is the radius of the circle?

http://mathcentral.uregina.ca/QQ/database/QQ.09.98/riddleberger1.html
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 15, 2013, 3:38 pm
On 4/15/2013 10:14 AM, Gramp's shop wrote:

feet apart and the depth of the arc at the center point is 2 inches. What is the radius of the circle?

R"6" according to Sketchup.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 15, 2013, 5:41 pm
On 4/15/2013 11:38 AM, Leon wrote:

Trigonometry concurs. :)
http://www.flickr.com/photos/gdguarino/8651887015/in/photostream/lightbox/
Thanks to the O.P. for a pleasant lunchtime puzzle.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 15, 2013, 6:22 pm
On 4/15/2013 1:41 PM, Greg Guarino wrote:

It was more fun to try to work it out for myself, but I just looked it up and there is (of course) a more direct way to find it.
Where H = the height of the arc (2") and W= the width of the base (60")
In our example that's:
2/2 + 60^2/8(2)= 1 + 3600/16 = 1 + 225 = 226
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 15, 2013, 7:26 pm
Greg Guarino wrote:

Greg, We both drew the same picture. How much math background do you have (if you don't mind me asking)?
Bill
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 15, 2013, 7:44 pm
On 4/15/2013 3:26 PM, Bill wrote:

little calculus in college. That would all have been in the '70s.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 17, 2013, 12:57 am
"Leon" wrote in message
On 4/15/2013 10:14 AM, Gramp's shop wrote:

R"6" according to Sketchup. ==========================================================================My calculator says that your program is right.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 17, 2013, 1:20 pm
On 4/16/2013 7:57 PM, CW wrote:

I'm glad you were able to verify the accuracy of your calculator. ;~)
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 15, 2013, 3:39 pm
On 4/15/13 10:14 AM, Gramp's shop wrote:

According to those cool calculators, 18'10".
--

-MIKE-

"Playing is not something I do at night, it's my function in life"
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 15, 2013, 4:10 pm
Hah! Now all I need to do is figure out how to draw an arc with an 18 foot radius :-) I have a couple of ideas and will post pix of the process.
On Monday, April 15, 2013 10:14:29 AM UTC-5, Gramp's shop wrote:

feet apart and the depth of the arc at the center point is 2 inches. What is the radius of the circle?

<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 15, 2013, 4:43 pm
On Mon, 15 Apr 2013 09:10:54 -0700, Gramp's shop wrote:

Bend a piece of thin cutoff around the points?
--
When fascism comes to America, it will be wrapped in the flag and
carrying a cross.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 15, 2013, 5:44 pm
On 4/15/2013 12:43 PM, Larry Blanchard wrote:

produce an arc of a circle. Will it matter? Might the resultant curve be subtly nicer than a circular arc? That's up to the designer.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 15, 2013, 7:10 pm
My plan exactly, Larry. I'm going to start with drilling screws into the waste side of the end points and the top of the arc, attach a thin strip of one-by with spring clamps and then add a couple of screws/clamps along the arc.
The other Larry
On Monday, April 15, 2013 11:43:27 AM UTC-5, Larry Blanchard wrote:

<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 15, 2013, 11:24 pm
"Larry Blanchard" wrote in message

+1
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 15, 2013, 5:20 pm
On 4/15/2013 11:10 AM, Gramp's shop wrote:

feet apart and the depth of the arc at the center point is 2 inches. What is the radius of the circle?

!8' string with a pencil died around one end. Nail in the ground on the other end.
Or use sketchup to print out a template.
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 15, 2013, 5:47 am
On 4/15/2013 12:20 PM, Leon wrote:

<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 16, 2013, 12:26 am
On 4/15/2013 12:47 AM, Richard wrote:

Did he say wanted the full circle or the 5' arc?
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
• posted on April 16, 2013, 1:10 am
Leon wrote:

He said he wanted the 5' Chord!