The **`sqrt()` function** in Ruby returns the *square root* of a non-negative number. 

Figure 1 shows the mathematical representation of the `sqrt()` function.

# Syntax
```ruby
sqrt(number)
```
# Parameter
`sqrt()` requires a non-negative number as a parameter. If the number is negative, a `DomainError` will be thrown.

# Return value
`sqrt()` returns the square root of the number sent as a parameter. 

# Example

print "sqrt(4):", Math.sqrt(4), "\n"

print "sqrt(0):", Math.sqrt(0), "\n"

print "sqrt(25):", Math.sqrt(25), "\n"

print "sqrt(4.5):", Math.sqrt(4.5), "\n"

What is Math.sqrt() in Ruby?

Ruby's `sqrt()` function returns the square root of a non-negative number or throws a DomainError.