Which method can be used to find right angles for reference lines?

The correct answer is based on the fact that all the methods listed can indeed be used effectively to establish right angles for reference lines, which is crucial in various construction and installation tasks.

Using the 3-4-5 triangle method is a fundamental technique derived from the Pythagorean theorem. By measuring a triangle where one side is 3 units long, the second side is 4 units long, and the hypotenuse is 5 units long, you can confidently create a right angle. This method is simple and does not require specialized equipment, making it accessible for many situations.

The use of arcs comes into play as well, particularly when laying out circles or curved lines. By plotting points equidistant from a central point (the radius), one can establish tangents that are perpendicular to the radius at the circumference, thus allowing for precise right angle formation in conjunction with other methods.

Optical equipment, such as theodolites or laser levels, can be employed to accurately measure angles and establish right angles over longer distances or in more complex layouts. This approach is particularly useful for larger projects where manual measurement may be less precise.

Therefore, employing any of these methods individually or in combination can help achieve accurate right angles, validating that the correct