How many grads are there in a full circle?

In the context of circular measurement, a full circle is defined as comprising 400 gradians, or "grads." This system of measurement is particularly useful in certain fields such as surveying and engineering, as it facilitates calculations and conversions.

In the gradian system, a right angle is defined as 100 gradians, allowing for easier mathematical operations when dealing with angles, especially during the conversion to other units like degrees. Therefore, when considering a complete revolution around a circle, it is divided into 400 units.

The other options present different measurements associated with angles, but they belong to varying systems. A full circle consists of 360 degrees, while some circles may be described using radians or other measurement systems, yet the gradian system specifically states there are 400 gradians, making it the correct choice.