Calculate the size of the unknown angle in this polygon.

b=70

Step-by-step explanation:

(5-2)180=540

540-83-225-84-78=70

70

Step-by-step explanation:

By adding all the angles, we get 470.

If we use the formula 180(n-2), where n is the number of sides, we get

180(5-2)

=180(3)

=540

540-470=70

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:

is there a picture

step-by-step explanation: