A parallel-plate capacitor has plates of area 326times104

Question

Compute each part of given problem:

Problem: A parallel-plate capacitor has plates of area 3.26×10⁴ m².

Part A: What plate separation is required if the capacitance is to be 1560pF? Assume that the space between the plates is filled with air?

Part B: What plate separation is required if the capacitance is to be 1560pF? Assume that the space between the plates is filled with paper.

I don't just need an answer, work and explanations/walkthrough would be much appreciated! Thank you.