Final answer:
A reference line is necessary when using a table saw to ensure straight and accurate cuts.
Step-by-step explanation:
When using the table saw, it is important to have a reference line on your board. A reference line helps you ensure that your cut is straight and accurate. It acts as a guide for guiding the board through the saw and helps you maintain control and precision.
Without a reference line, it can be difficult to make clean and precise cuts, resulting in uneven or jagged edges. This is especially important when working on projects that require precise measurements and fittings, such as furniture making or cabinetry.
By marking a reference line on your board, you have a visual guide to follow, allowing you to make accurate cuts and achieve the desired outcome.