Final answer:
On a number line, 8.78 is located to the right of 8.63 and between 8 and 9.
Step-by-step explanation:
On a number line, 8.78 would be located to the right of 8.63, because on a number line, numbers increase in value as you move to the right. Therefore, any number greater than 8.63 would appear to its right. Option B is incorrect because 8.78 is between 8 and 9, not between 7 and 8. Option C is incorrect because 8.78 is greater than 8.71, so it would be to the right. And option D is correct; 8.78 is indeed between 8 and 9.