Can someone help me?

shape is a Pentagon (has 5 sides)

Sum of interior angles is 540°

x = 90°

m∠B = 90°

m∠E = 100°

Step-by-step explanation:

to find the sum of the interior angles you take the number of sides, deduct two, and multiply by 180

a 5-sided figure would be (n - 2)·180° = 3(180) = 540°

add together all five angle measures and set equal to 540; combine like terms and solve for 'x'

220 + 130 + 130 + x + x + 10 = 540

350 + 2x + 10 = 540

2x + 360 = 540

2x = 180

x = 90

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: