# Math Help - Polygon

1. ## Polygon

What is the perimeter, in units, of a regular 11-sided polygon with sides of length .36363636… units?

I don't know how to find the answer to this problem. Please use words that a 7th grader can understand. Thanks!

2. ## Re: Polygon

The perimeter is the sum of all the sides of a figure. For instance, the perimeter of a triangle is the sum of the lengths of the three sides. the perimeter of a rectangle is the sum of the length of the four sides. Can you now find the perimeter of your polygon.

3. ## Re: Polygon

What is the perimeter, in units, of a regular 11-sided polygon with sides of length .36363636… units?

I don't know how to find the answer to this problem. Please use words that a 7th grader can understand. Thanks!
First of all, it would help if you wrote the length of each side as a fraction, as they are exact.

\displaystyle \begin{align*} x &= 0.363636\dots \\ 100x &= 36.363636\dots \\ 100x - x &= 36.363636\dots - 0.363636\dots \\ 99x &= 36 \\ x &= \frac{36}{99} \\ x &= \frac{4}{11} \end{align*}

So that means each side is \displaystyle \begin{align*} \frac{4}{11} \end{align*} of a unit in length, and since there are 11 sides, the perimeter is \displaystyle \begin{align*} 11 \times \frac{4}{11} = 4 \end{align*} units.

4. ## Re: Polygon

Originally Posted by Prove It
First of all, it would help if you wrote the length of each side as a fraction, as they are exact.

\displaystyle \begin{align*} x &= 0.363636\dots \\ 100x &= 36.363636\dots \\ 100x - x &= 36.363636\dots - 0.363636\dots \\ 99x &= 36 \\ x &= \frac{36}{99} \\ x &= \frac{4}{11} \end{align*}

So that means each side is \displaystyle \begin{align*} \frac{4}{11} \end{align*} of a unit in length, and since there are 11 sides, the perimeter is \displaystyle \begin{align*} 11 \times \frac{4}{11} = 4 \end{align*} units.
Thank you very much!!
I learned this kind of math before but I just forgot!!
Thanks!! I will remember how to do these kinds of problems now!