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Topic: Trying to find perimeter of a regular pentagon
Replies: 36   Last Post: May 31, 2013 9:26 PM

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JT

Posts: 1,149
Registered: 4/7/12
Re: Trying to find perimeter of a regular pentagon
Posted: May 28, 2013 12:06 PM
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On 28 Maj, 17:15, 130bcd <carl.sundqu...@gmail.com> wrote:
> Hello,
>
> I have unsuccessfully tried to find the perimeter of a pentagon. The "radius" to the vertices is 130, which I tried to convert into 5 triangles but I can't find a formula for determining the length of the 3rd side of an isosceles triangle.
>
> The two equal length sides would, of course be 130 and the angle between them would be 72.
>
> Help, please!


As always you would have to start dividing into two right angled
triangles i guess that gives 31 degree angle at centrum, then my
trigonometry is to weak to go on from but basicly calculate base and
height using trig formulas and then multiply height 10
times to get the perimeter or ?.

But there is possibly a much easier ratio solution using fractions.


Date Subject Author
5/28/13
Read Trying to find perimeter of a regular pentagon
130bcd
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
Barry Schwarz
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
Ken.Pledger@vuw.ac.nz
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
Ken.Pledger@vuw.ac.nz
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
David Bernier
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
Brian Q. Hutchings
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/30/13
Read Re: Trying to find perimeter of a regular pentagon
RGVickson@shaw.ca
5/31/13
Read Re: Trying to find perimeter of a regular pentagon
Brian Q. Hutchings
5/31/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/31/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/31/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/31/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/31/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/31/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/31/13
Read Re: Trying to find perimeter of a regular pentagon
Brian Q. Hutchings
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
Brian Q. Hutchings
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
Brian Q. Hutchings
5/28/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/29/13
Read Re: Trying to find perimeter of a regular pentagon
Richard Tobin
5/29/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/29/13
Read Re: Trying to find perimeter of a regular pentagon
Richard Tobin
5/29/13
Read Re: Trying to find perimeter of a regular pentagon
Brian Q. Hutchings
5/29/13
Read Re: Trying to find perimeter of a regular pentagon
JT
5/29/13
Read Re: Trying to find perimeter of a regular pentagon
Brian Q. Hutchings
5/30/13
Read Re: Trying to find perimeter of a regular pentagon
Graham Cooper
5/30/13
Read Re: Trying to find perimeter of a regular pentagon
RGVickson@shaw.ca

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