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Atn Function

Syntax

`Atn(`number`)`
`number`

Use: Required

Data Type: Numeric

Any numeric expression, representing the ratio of two sides of a right angle triangle.

Return Value

The return value is a Double representing the arctangent of `number` in the range -pi/2 to pi/2 radians.

Description

Takes the ratio of two sides of a right triangle (`number`) and returns the corresponding angle in radians. The ratio is the length of the side opposite the angle divided by the length of the side adjacent to the angle.

Rules at a Glance

• If no number is specified, a runtime error is generated.

• The return value of Atn is in radians, not degrees.

Example

```<%
Const Pi = 3.14159
Dim dblRatio, dblAtangent, dblDegrees

dblSideOpp = 75.5

dblAtangent = Atn(dblRatio)
' convert from radians to degrees
dblDegrees = dblAtangent * (180 / Pi)
Response.Write dblDegrees & " Degrees"
%>```

Programming Tips and Gotchas

• To convert degrees to radians, multiply degrees by pi/180.