Answer
The planes are parallel.
Work Step by Step
Two planes that are tangent to a sphere at the endpoints of a diameter will never intersect and will always be a diameters distance apart, therefore they are parallel.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.