# Math.Sqrt(Double) Method

## Definition

Returns the square root of a specified number.

``````public:
static double Sqrt(double d);``````
``public static double Sqrt (double d);``
``static member Sqrt : double -> double``
``Public Shared Function Sqrt (d As Double) As Double``

#### Parameters

d
Double

The number whose square root is to be found.

#### Returns

Double

One of the values in the following table.

`d` parameter Return value
Zero or positive The positive square root of `d`.
Negative NaN
Equals NaNNaN
Equals PositiveInfinityPositiveInfinity

## 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.

``````// Create an array containing the area of some squares.
Tuple<string, double>[] areas =
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) };

Console.WriteLine("{0,-18} {1,14:N1} {2,30}\n", "City", "Area (mi.)",
"Equivalent to a square with:");

foreach (var area in areas)
Console.WriteLine("{0,-18} {1,14:N1} {2,14:N2} miles per side",
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
``````
``````open System

// Create a list containing the area of some cities.
let areas =
"New York City", 302.6
"Los Angeles", 468.7
"Detroit", 138.8
"Chicago", 227.1
"San Diego", 325.2 ]

printfn "%-18s %14s} %2s\n" "City" "Area (mi.)" "Equivalent to a square with:"

for city, area in areas do
printfn \$"{city,-18} {area,14:N1} {Math.Round(Math.Sqrt(area), 2),14:N2} miles per side"

// 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
``````
``````Module Example
Public Sub Main()
' Create an array containing the area of some squares.
Dim areas() As Tuple(Of String, Double) =
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) }

Console.WriteLine("{0,-18} {1,14:N1} {2,30}", "City", "Area (mi.)",
"Equivalent to a square with:")
Console.WriteLine()
For Each area In areas
Console.WriteLine("{0,-18} {1,14:N1} {2,14:N2} miles per side",
area.Item1, area.Item2, Math.Round(Math.Sqrt(area.Item2), 2))
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
``````