If a circle's circumference is 15 inches what is its radius? Leave the symbol pi in your answer.

Question

anonymous · Answer

Do you remember the formula for the circumference of a circle?

anonymous · Answer

c=2 pi r

anonymous · Answer

Alright how would you make it so that only r is on the right hand side?

anonymous · Answer

I can't remember we just got back on this section in class and i'm confused.

anonymous · Answer

Its alright, just think whats the opposite of multiplication?

anonymous · Answer

division

anonymous · Answer

so how would we "cancel" the multiplication by 2*pi on the right hand side?

anonymous · Answer

divide by 2 pi?

anonymous · Answer

yes, but we can't do it to just the right side an not the left side, if we did they wouldn't be equal anymore! So, what is your new formula for the radius you just developed?

anonymous · Answer

*right side and not

anonymous · Answer

c/2 pi r=2 pi r/ 2 pi r

anonymous · Answer

? confused

anonymous · Answer

Sorry friend was having a small panic attack, had to help her. but yes thats right so the final formula once simplifed is
c/(2Pi)=r

anonymous · Answer

sub in c = 15 and get your answer