OK...
If you know the volume of P and t and i.
Then Use this: r=P÷i÷t
I think you mean that, right?
X^4=256
x^4-256=0
(x^2)^2-(16)^2=0
(x^2+16)(x^2-16)=0
either x^2+16=0
it gives complex roots.
or x^2-16=0
or x^2-4^2=0
(x+4)(x-4)=0
either x+4=0,x=-4
or x-4=0
x=4
Let the given sides be "a" and "b" and the unknown side be "c". The Law of Cosines tells you
.. c^2 = a^2 +b^2 -2ab*cos(C)
.. c^2 = 2^2 +3^2 -2*2*3*cos(60°)
.. c^2 = 7
.. c = √7 ≈ 2.6458
The third side of the triangle is √7, about 2.6458.