Answer
$x =a \sin \phi \cos \theta; y=a \sin \phi \sin \theta;$ and $z= a \cos \phi$
Work Step by Step
Let us consider $Z$ be the axis parameter and the spherical parameters of a sphere can be written as: $\rho, \theta, \phi,$. Assume that $a$ be the radius of the sphere.
Here, $\rho=a, \theta \in [0, 2\pi]$ and $\phi \in [0, 2\pi]$
Thus, the parametric description for a sphere with rectangular coordinates can be expressed as:
$x =a \sin \phi \cos \theta; y=a \sin \phi \sin \theta;$ and $z= a \cos \phi$
