• Definition
• Behavior
• Example
`\$degreesToRadians`

New in version 4.2.

Converts an input value measured in degrees to radians.

`\$degreesToRadians` has the following syntax:

`.leafygreen-ui-iokrs{color:inherit;font-size:13px;font-family:'Source Code Pro',Menlo,monospace;line-height:24px;}`.leafygreen-ui-1v41da1{border-spacing:0;width:100%;}.leafygreen-ui-7razhx{border-spacing:0;vertical-align:top;padding:0 16px;}{ \$degreesToRadians: <expression> }``

`\$degreesToRadians` takes any valid expression that resolves to a number.

By default `\$degreesToRadians` returns values as a `double`. `\$degreesToRadians` can also return values as a 128-bit decimal as long as the `<expression>` resolves to a 128-bit decimal value.

If the argument resolves to a value of `null` or refers to a field that is missing, `\$degreesToRadians` returns `null`. If the argument resolves to `NaN`, `\$degreesToRadians` returns `NaN`. If the argument resolves to negative or positive infinity, `\$degreesToRadians` negative or positive infinity respectively.

Example
Results
`{ \$degreesToRadians: NaN }`
`NaN`
`{ \$degreesToRadians: null }`
`null`
`{ \$degreesToRadians : Infinity}`
`Infinity`
`{ \$degreesToRadians : -Infinity }`
`-Infinity`

The `trigonometry` collection contains a document that contains three angles measured in degrees:

``{  "angle_a" : NumberDecimal("53.13010235415597870314438744090659"),  "angle_b" : NumberDecimal("36.86989764584402129685561255909341"),  "angle_c" : NumberDecimal("90")}``

The following aggregation operation uses the `\$degreesToRadians` expression to convert each value to its radian equivalent and add them to the input document using the `\$addFields` pipeline stage.

``db.trigonometry.aggregate([  {    \$addFields: {      "angle_a_rad" : { \$degreesToRadians : "\$angle_a"},      "angle_b_rad" : { \$degreesToRadians : "\$angle_b"},      "angle_c_rad" : { \$degreesToRadians : "\$angle_c"}    }  }])``

The operation returns the following document:

``{  "_id" : ObjectId("5c50aec71c75c59232b3ede4"),  "angle_a" : NumberDecimal("53.13010235415597870314438744090660"),  "angle_b" : NumberDecimal("36.86989764584402129685561255909341"),  "angle_c" : NumberDecimal("90"),  "angle_a_rad" : NumberDecimal("0.9272952180016122324285124629224290"),  "angle_b_rad" : NumberDecimal("0.6435011087932843868028092287173227"),  "angle_c_rad" : NumberDecimal("1.570796326794896619231321691639752")}``

Since `angle_a`, `angle_b`, and `angle_c` are stored as 128-bit decimals, the output of `\$degreesToRadians` is a 128-bit decimal.