Geometry Help

May 15, 2011 13 Replies

I'm trying to draw a 7 sided polygon using MS Paint. I found a program that is supposed to allow me to draw any angle in Paint. I'm starting to question it's accuracy because of all the problems I'm having. But assume for now the program is accurate. I have tried 25.71*, 54.43*, 64.285*, If I start with a vertical line, then rotate it to (x) angle, What is (x) angle so I can add it to itself 6 time to make the 7 sided poly.

formatting link
Here's a visual. Thanks, Mikek



PS. electronics related, making an inductor form, similar to this six sided form.

formatting link


You need to add it to itself 7 times to make a heptagon.

N-gon 3 4 5 6 7 8 N Angle 120 90 72 60 51.4285 45 360/N

A six sided one would be a lot easier to build!

Regards, Martin Brown

51.4286 degrees news:652mouhmuvtjsv9b2fnolpnektf24@4ax.com

Don't know about Paint, but...

51 degrees (3/7) for a heptagon.

formatting link

formatting link

formatting link

formatting link

I don't know, maybe semantics if I have one and add it to itself six times, I have 7.

I don't know what those two lines are supposed tell me.

Here's the program I'm rotating with.

formatting link

It was, now I want 7 sides.

Hi John, I have one try at 51.43 and it could be right for the top left and right sides, but what is the next angle From vertical? It measures around 12 degrees but doesn't work when using the program.

formatting link
Could be I'm not using the program for it's designed purpose. Your link didn't work. Thanks, Mikek

But you have to go 360 degrees to get back where you were. For a triangle, you have to turn three times, 120 degrees each to get back to the original bearing.

For each N-gon (first row) the angle (second row) you need to turn at each corner to complete the N-gon. For a triangle (equilateral) at each corner you would turn 120 degrees (60 degree interior angle).

360/7 = 51.42857 change in direction, or an interior angle of 128.57143 degrees.

I have spent time working with 51.43 and I'll try some more. So I start with a vertical line and rotate it to 51.43, now for the second side, do I add 51.43 + 51.43 = 102.86? If so, I'm feeling the rotation program isn't working for my need. If I can get 3 sides I can flip it horizontal for the other 3 sides, and then draw in the bottom. Thanks, Mikek

Use a 7/2 or 7/3 method:

halfway down the page.

formatting link

It looks like you have to enter 51.43 to get the first skews and stretches, then 102.86 to get the next set, and so on around the circle.

~64.286 degrees is correct.

The sum of interior angles in a polygon is (n-2) * 180°, so you want

1/2 * 1/7 * (5 * 180) degrees = 450/7 degrees.

Maybe try something other than MS paint, like a real CAD program?

Best regards, Spehro Pefhany

"it's the network..." "The Journey is the reward" speff@interlog.com Info for manufacturers: http://www.trexon.com Embedded software/hardware/analog Info for designers: http://www.speff.com

You increment the bearing 51.43 degrees at each corner if the drawing program uses absolute directions. If it uses relative directions you just use the

51.43 degree number. "Flipping" it just adds confusion.

Use your calculator or a small program or script (it could probably be done on a spreadsheet) that gives you coordinates for the points, then draw them while referring to the "x,y" display on your paint program, then connect the dots.

Have Fun! Rich

Join the Discussion

Have something to add? Share your thoughts — no account required.

Didn't find your answer?

Ask the community — no account required