Britannica Sources used in this answer

How many radians are in one complete revolution?

Created from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles.

Diagram of a right triangle labeled with sides a, b, and hypotenuse c, alongside formulas for the six trigonometric functions-sine, cosine, tangent, cosecant, secant, and cotangent-each defined by ratios of the triangle's sides. — trigonometry Based on the definitions, various simple relationships exist among the functions. For example, csc A = 1/sin A, sec A = 1/cos A, cot A = 1/tan A, and tan A = sin A/cos A.

In trigonometry, there are $2 π$ radians in one complete revolution.123