Project Euler: Problem 3

Euler_3

def is_prime?(num)
  2.upto(num-1) { |i| return false if ((num % i) == 0) }
  true
end

def largest_prime(num)
  primes = []
	1.upto(num) { |i| primes << i if num % i == 0 && is_prime?(i) }

	p primes.last
end