Which tool is primarily used for measuring angles in surveying?

The theodolite is primarily used for measuring angles in surveying due to its precision and versatility. This instrument can measure both horizontal and vertical angles, making it essential for various surveying tasks, including setting out construction sites, aligning structures, and determining property boundaries.

The design of a theodolite allows for accurate angular measurements because it has a telescope for sighting distant objects and graduated circles for precise readings. When surveyors need to establish angles within their work, the theodolite provides the required level of accuracy and reliability, which is crucial in ensuring the integrity of the survey.

Other tools mentioned, such as the laser level, clinometer, and protractor, serve different functions. A laser level primarily aids in establishing horizontal or vertical reference lines, while a clinometer is used to measure slopes or elevation angles, and a protractor is typically a two-dimensional tool used to measure angles on a flat surface. None of these tools can match the comprehensive angular measurement capabilities of a theodolite in the context of surveying tasks.