5/20 = 1/4. All the rest of the fractions reduce to 1/5.
a regular polygon has all equal sides.
a PENTA=5, pentagon has 5 sides, so a regular pentagon has 5 equal sides.
![\bf \textit{area of a polygon}\\\\ A=\cfrac{1}{2}ap~~ \begin{cases} a=apothem\\ p=perimeter\\[-0.5em] \hrulefill\\ a=K\\ p=\stackrel{3+3+3+3+3}{15} \end{cases}\implies A=\cfrac{1}{2}K15\implies A=\cfrac{15}{2}K](https://tex.z-dn.net/?f=%20%5Cbf%20%5Ctextit%7Barea%20of%20a%20polygon%7D%5C%5C%5C%5C%20A%3D%5Ccfrac%7B1%7D%7B2%7Dap~~%20%5Cbegin%7Bcases%7D%20a%3Dapothem%5C%5C%20p%3Dperimeter%5C%5C%5B-0.5em%5D%20%5Chrulefill%5C%5C%20a%3DK%5C%5C%20p%3D%5Cstackrel%7B3%2B3%2B3%2B3%2B3%7D%7B15%7D%20%5Cend%7Bcases%7D%5Cimplies%20A%3D%5Ccfrac%7B1%7D%7B2%7DK15%5Cimplies%20A%3D%5Ccfrac%7B15%7D%7B2%7DK%20)
Hi hi hi hi hi hi hi hi hi hi hi hi hi
5y+2(3y-1)=__y-(y+2)
5y+6y-2=__y-y-2
11y-2+2+y=__y
12y=___y
so 12