The circumference of a circle can be found using the formula C = 2r. Which is an equivalent equation solved for r?

r = C
r = C(2)
r = r equals StartFraction C Over 2 pi EndFraction.
r = r equals StartFraction 2 pi Over C EndFraction.

r = C/(2π)

Step-by-step explanation:

C = 2πr

Divide both sides by 2π

C/(2π) = r

r = C/(2π)

since your problem is x^4 = 81, what you have to undeo is the "to the fourth power" part.

the inverse (opposite operation) of "to the fourth power" is "to the fourth root".

  (x^4) ^ ¼   = 81 ^ ¼  

  81 = 3^4     so (3 ^ 4) ^ ¼   =   3 ^ 1   = 3

by hand: (3 ^ 4) ^ ¼   =   3 ^ (4 x ¼) = 3 ^ 1   = 3   (when you take a power to a power, multiply the exponents.)

or, do it by calculator. one way of finding the fourth root is to use ^ (1/4)

step-by-step explanation:

step-by-step explanation:

your mom