Final answer:
The question relates to Physics, particularly dealing with the calculation of magnetic fields in square loops and combining principles of electromagnetism with basic geometry, such as area and perimeter of a square.
Step-by-step explanation:
The subject of this question falls under Physics, where the focus is on calculating magnetic fields in square loops and understanding the geometry and areas associated with square shapes in different contexts. To calculate magnitudes of magnetic fields, one must apply knowledge of electromagnetism, especially concepts as outlined by Ampère's Law. The reference to areas and perimeters indicates a crossover into basic geometry. For example, calculating the area of a square involves squaring the length of one side (a²), while the perimeter is four times one side (4a). Similarly, when converting from a circular area to a comparable square area, you compare the areas such that the square's area is slightly less due to fitting the circle within it. In the context of a physics problem involving magnetic fields and circuits, we apply these geometric concepts to determine induced currents or magnetic field strengths at specific points within a circuit.