Recursive (slow) solution to Fibonacci validation exercise

Fibrec

def fibonacci(n)	
	if n <= 1
		n
	else
		fibonacci(n-1) + fibonacci(n-2)
	end
end

def isFibonacci(soughtNumber)
	return isFibonacci?(soughtNumber, 1)
end

def isFibonacci?(soughtNumber, currentFibonacciIndex)
	currentFibonacciNumber = fibonacci(currentFibonacciIndex)
	isFibonacciNumber = currentFibonacciNumber == soughtNumber
	if (isFibonacciNumber)
		return true
	end

	outOfRange = currentFibonacciNumber > soughtNumber
	if (outOfRange)
		return false
	end

	nextFibonacciIndex = currentFibonacciIndex + 1
	return isFibonacci?(soughtNumber, nextFibonacciIndex)
end

#Call 2nd method for Fibonacci verification
  puts isFibonacci(233)