i have no idea how to solvethis wud sum1 plz help me! πr2 = 21 pi x r"2" = 21

Follow Math Help Forum on Facebook and Google+

Originally Posted by mezzie i have no idea how to solvethis wud sum1 plz help me! πr2 = 21 pi x r"2" = 21 What is the question? Is it rearrange this to something like r= some expression possibly in terms of 21 and pi ...? Divide both sides by to get: Now take the sqruare root (we want the positive root because is presumably the radius of a circle): RonL