The formula below gives the area of a semi-circle, a, with a radius of r. solve the formula for the radius.

So, lets start by making the fifth-degree polynomial with three terms in standard form. but, first lets look at how to make a fifth-degree polynomial. 

fifth degree polynomials are also known as quintic polynomials. quintics have these characteristics:

1.one to five roots.2. zero to four extrema.3. one to three inflection points.4. no general symmetry.5. it takes six points or six pieces of information to describe a quintic function.6.roots are not solvable by radicalsso we could = 3x^5 + 20x^4 - 10x^3 -240x^2 -250x + 200.  so now we have to make sure it's in standard it is. but how do we know?   in  order  to write any  polynomial  in  standard form, you look at the  degree  of each term. you then write each term in  order  of  degree, from highest to lowest, left to write. the  degree  of a  polynomial  is the same as the  degree  of the highest term, so this expression is called a  fifth degree  trinomial.now we are done with prt a.