Which of the following angles can be trisected using only a compass and straightedge?
a.90
b.80
c.70
d.100

The correct option is (A) 90°

Step-by-step explanation:

The angles can be trisected which  constructive angle θ, an angle of measure 3θ can be trivially trisected.

So, the angle in option (A) is written as 3θ.

3θ=3(30°)

but rest options can't write as 3θ.

Hence, the correct option is (A) 90°

phosphate, calcium ion, chloride ion, neon atom

step-by-step explanation:

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: