Calculadora de Arco Cosseno
- Created by
- Renato Passos, Eng. de Software
- Reviewed by
- Renato Passos, Eng. de Software
Last updated: Apr 18, 2026
Formula
ângulo = arccos(valor) × 180/π
About this calculator
The Arccosine Calculator converts a value between -1 and 1 into the angle whose cosine equals that value. The result is displayed in degrees. The arccosine function is the inverse of the cosine function, meaning if cos(θ) = x, then arccos(x) = θ. The calculator uses the formula: angle (in degrees) = arccos(value) × 180/π.
This tool is useful in various contexts, such as solving triangles where you need to find an angle from an adjacent side and the hypotenuse. It is also applied in physics, engineering, and computer graphics, for example, to determine angles of vectors or compute force components. Students and professionals can use it to verify manual calculations or solve problems quickly.
Important precautions: the input value must be strictly within the closed interval from -1 to 1. Values outside this range are not valid for the real arccosine function. Also, remember that arccosine returns angles in the range of 0° to 180° (or 0 to π radians). Check that the result is in the expected quadrant for your problem.
Frequently asked questions
What does arccosine mean?
Arccosine is the inverse function of cosine. Given a value x, it returns the angle whose cosine is x.
What values can I enter in the calculator?
Only values between -1 and 1, inclusive. Outside this range, the real arccosine is not defined.
Is the result in degrees or radians?
The result is displayed in degrees. If you need radians, divide the result by 180 and multiply by π.
What is the range of possible angles?
Arccosine returns angles between 0° and 180° (0 to π radians).
Can I use this calculator to find an angle in a right triangle?
Yes, if you know the adjacent side and the hypotenuse, the cosine of the angle is the ratio. Use arccosine to get the angle.