The distance from Fp1 to O1 through C3 is 24 cm. What is the distance from C3 to P3?

To determine the distance from C3 to P3 based on the provided information, it's important to apply the principles of the 10-20 system of electrode placement, which is commonly used in EEG studies. In this system, distances between various electrode positions are defined relative to reference points on the head.

The distance from Fp1 (frontal point) to O1 (occipital point) through C3 (central point) measures a total of 24 cm. Each section of this path comprises specific ratios of the total distance defined in the 10-20 system. In this context, knowing the total length helps in calculating the distance between other electrodes.

Specifically, if we break down the arrangement: the distance from Fp1 to C3 should be approximately equal to the distance from C3 to O1 due to the symmetry in the placement of the electrodes. Therefore, if you consider the distances along the path from Fp1 to O1 (24 cm), each segment along that pathway can be thought of as an individual proportional segment.

The point C3 is situated approximately at the midpoint to both the frontal and occipital points, allowing for the determination of relative positioning of adjacent electrodes such as C3 and P3.