Find the missing segment

The unknown side is 140

Step-by-step explanation:

Let the unknown side be x

Using ratios

90         90+36

=

x            x+56

90         126

=

x            x+56

Using cross products

90(x+56) = 126x

Distribute

90x+5040 = 126x

Subtract 90x

5040 = 36x

Divide by 36

140 =x

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: