## Atn Function

This standard VB function returns the angle (in radians) for the arctangent of the specified number.

##### Syntax

Atn(number)

Argument
Description

number

Any valid numeric expression

##### Returns

The arctangent of number.

##### Usage

The Atn function assumes number is the ratio of two sides of a right triangle: the side opposite the angle to find and the side adjacent to the angle. The function returns a single-precision value for a ratio expressed as an integer, a currency, or a single-precision numeric expression. The return value is a double-precision value for a long, variant, or double-precision numeric expression.

To convert radians to degrees, multiply by (180/PI). The value of PI is approximately 3.14159.

##### Example

This example finds the roof angle necessary for a house with an attic ceiling of 8 feet (at the roof peak) and a 16-foot span from the outside wall to the center of the house. The Atn function returns the angle in radians; it is multiplied by 180/PI to convert it to degrees.

Sub Button_Click
Dim height As Single, span As Single, angle As Single
Dim PI As Single
PI = 3.14159
height = 8
span = 16
angle = Atn(height/span) * (180/PI)
End Sub