# Math.Sqrt Method

Returns the square root of a specified number.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)

## Syntax

``````'Declaration
<SecuritySafeCriticalAttribute> _
Public Shared Function Sqrt ( _
d As Double _
) As Double
``````
``````[SecuritySafeCriticalAttribute]
public static double Sqrt(
double d
)
``````

#### Return Value

Type: System.Double

Value of d

Returns

Zero, or positive

The positive square root of d.

Negative

NaN

If d is equal to NaN or PositiveInfinity, that value is returned.

## Examples

The square root of the area of a square represents the length of any side of the square. The following example displays the area of some cities in the United States and gives an impression of each city's size if it were represented by a square.

``````Module Example
Public Sub Demo(outputBlock As System.Windows.Controls.TextBlock)
outputBlock.FontFamily = New System.Windows.Media.FontFamily("Courier New")

' Create an array containing the area of some squares.
Dim areas() As Tuple(Of String, Double) =
{ Tuple.Create("Sitka, Alaska", 2870.3),
Tuple.Create("New York City", 302.6),
Tuple.Create("Los Angeles", 468.7),
Tuple.Create("Detroit", 138.8),
Tuple.Create("Chicago", 227.1),
Tuple.Create("San Diego", 325.2) }

outputBlock.Text += String.Format("{0,-18} {1,14:N1} {2,30}", "City", "Area (mi.)",
"Equivalent to a square with:") + vbCrLf
outputBlock.Text += vbCrLf
For Each area In areas
outputBlock.Text += String.Format("{0,-18} {1,14:N1} {2,14:N2} miles per side",
area.Item1, area.Item2,
Math.Round(Math.Sqrt(area.Item2), 2)) + vbCrLf
Next
End Sub
End Module
' The example displays the following output:
'    City                   Area (mi.)   Equivalent to a square with:
'
'    Sitka, Alaska             2,870.3          53.58 miles per side
'    New York City               302.6          17.40 miles per side
'    Los Angeles                 468.7          21.65 miles per side
'    Detroit                     138.8          11.78 miles per side
'    Chicago                     227.1          15.07 miles per side
'    San Diego                   325.2          18.03 miles per side
``````
``````using System;
using System.Windows.Media;

public class Example
{
public static void Demo(System.Windows.Controls.TextBlock outputBlock)
{
outputBlock.FontFamily = new FontFamily("Courier New");
// Create an array containing the area of some squares.
Tuple<string, double>[] areas =
{ Tuple.Create("Sitka, Alaska", 2870.3),
Tuple.Create("New York City", 302.6),
Tuple.Create("Los Angeles", 468.7),
Tuple.Create("Detroit", 138.8),
Tuple.Create("Chicago", 227.1),
Tuple.Create("San Diego", 325.2) };

outputBlock.Text += String.Format("{0,-18} {1,14:N1} {2,30}\n\n", "City", "Area (mi.)",
"Equivalent to a square with:");

foreach (var area in areas)
outputBlock.Text += String.Format("{0,-18} {1,14:N1} {2,14:N2} miles per side\n",
area.Item1, area.Item2, Math.Round(Math.Sqrt(area.Item2), 2));
}
}
// The example displays the following output:
//    City                   Area (mi.)   Equivalent to a square with:
//
//    Sitka, Alaska             2,870.3          53.58 miles per side
//    New York City               302.6          17.40 miles per side
//    Los Angeles                 468.7          21.65 miles per side
//    Detroit                     138.8          11.78 miles per side
//    Chicago                     227.1          15.07 miles per side
//    San Diego                   325.2          18.03 miles per side
``````

## Version Information

#### Silverlight

Supported in: 5, 4, 3

#### Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

#### XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

## Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.