Enter a value x into the calculator. The calculate will evaluate and display the inverse cosine of the angle using the arccosine formula.

## Inverse Cosine Formula

The following formula can be used to calculate an angle from any cosine value.

Arccosine(x) = C

Cosine C = x

- Where AC is arc cosine, which is the same as saving inverse cosine
- x is a cosine value of two sides of a triangle.

## Inverse Cosine Definition

An inverse cosine is used to calculate an angle given the ratio of the opposite to adjacent sides of that angle.

## Inverse Cosine Example

How to calculate inverse cosine.

**First, find the ratio of the adjacent side to the opposite side.**These are the sides of the angle.

**Next, calculate the angle.**Calculate the angle using the inverse cosine.

## FAQ

**What is the inverse cosine?**

The inverse cosine is also known as the arc cosine and is used to calculate the value of an angle when the cosine of that angle is known.

**What is arc cosine?**

Arc cosine is just another way of saying the inverse cosine. The formula is the same as the inverse cosine.