Cheyenne is playing a board game. Her score was −140 at the start of her turn, and at the end of her turn her score was −360. What was the change in Cheyenne's score from the start of her turn to the end of her turn?

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:

answer: answer is b.

[m < b = 120º]

step-by-step explanation:

the answer is b.

64

step-by-step explanation:

c=2πr=2·π·8≈64

br tat so much r