x^0=1 so you can cancel it out. when a number has a negavite exponent, you have to invert it. That means y^-6 goes at the denominator and becomes y^6 and z^-6 goes up to the numerator and becomes z^6.
Since the equation for solving circumference is 2r, you can see that 2r = 46. Dividing 2 on both sides will give you r, or the radius. Hope this helped! :)
r, you can see that 2