Final Answer:
Lines that occur 3.14 inches apart on the finished radiograph are caused by the grid used during the imaging process.
Step-by-step explanation:
The lines appearing 3.14 inches apart on a finished radiograph are a result of the grid used in radiography. The grid, a device positioned between the X-ray tube and the image receptor, helps improve image quality by reducing scattered radiation. The lines, known as grid lines, occur due to the lead strips within the grid. These strips are interspaced at regular intervals, and their visibility on the radiograph is influenced by factors such as focus distance and alignment. The presence of these lines indicates proper grid usage, enhancing the clarity and accuracy of the radiographic image.