What is the first step to use 3D Trig to calculate angles?

To utilize 3D trigonometry for calculating angles, the initial step involves drawing a right-angled triangle. This is because trigonometric functions, such as sine, cosine, and tangent, fundamentally rely on the properties of right-angled triangles.

In 3D trigonometry, you often decompose a three-dimensional scenario into two-dimensional triangles which are right-angled. By establishing a right-angled triangle, you can apply the appropriate trigonometric ratios to solve for unknown angles or lengths. This foundational concept is key to extending calculations into three dimensions, as it helps to understand the relationships between different sides and angles in the context of 3D geometry.

The other approaches, such as measuring with a compass or using a protractor, do not provide the necessary geometric foundation for applying trigonometric principles effectively. Additionally, drawing a square does not relate directly to the principles involved in angle calculations in 3D space.