In capacitive electro stimulation, electrodes are placed on opposite sides of a limb. A potential difference is applied to the electrodes, which is believed to be beneficial in treating bone defects and breaks. If the capacitance is measured to be 0.59 pF, the electrodes are 4.0 cm2 in area, and the limb is 3.0 cm in diameter, what is the (average) dielectric constant of the tissue in the limb?