Method

# ACos

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## Description

Returns the [arccosine](http://en.wikipedia.org/wiki/Arccosine) of the value specified. The arccosine is the angle whose cosine is value. The returned angle is given in radians.

## Usage

``` xojo
result = ACos(value)
```

| Part   | Type                             | Description                           |
|--------|----------------------------------|---------------------------------------|
| result | `Double</api/data_types/double>` | The arc cosine of *value*.            |
| value  | `Double</api/data_types/double>` | The value you want the arc cosine of. |

## Notes

The <span class="title-ref">ACos</span> function returns the angle (in radians) of the cosine passed to it. To convert the result from radians to degrees, multiply it by 180/Pi.

## Sample code

This example uses the <span class="title-ref">ACos</span> function to return the arc cosine of a number.

``` xojo
Var d As Double
Const Pi = 3.14159265
d = ACos(0.5) ' returns 1.0471976
d = ACos(0.5) * 180 / Pi ' returns 60
```

## Compatibility

|                       |     |
|-----------------------|-----|
| **Project Types**     | All |
| **Operating Systems** | All |

<div class="seealso">

`Cos</api/math/cos>`, `Tan</api/math/tan>`, `Atan</api/math/atan>` functions

</div>