Answer: Henry needs to travel a total of 3000 meters to get to Cole, who has already traveled 900 meters.
Explanation:
Since one kilometer is equal to 1000 meters, and Henry is 3 kilometers away from Cole, he needs to travel 3 * 1000 = 3000 meters to get to Cole.
So, Henry needs to travel a total of 3000 meters to get to Cole, who has already traveled 900 meters.