The next three terms of the sequence are 19, 23, and 27.
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Arithmetic sequences
⇒ An arithmetic sequence is a sequence that adds or subtracts the same amount to get to the next term. The amount is known as the common difference. Here, the common difference is 4.
We need to know the common difference to find the next term. First we'll find the term that comes after 15 by adding 15 + 4, which is 19. So, the next term is calculated to be 19.
We still need to find the term that comes after 19. So we add 19 + 4 which is 23. The next term is 23.
For the last term we repeat the process, only this time, we'll add 23 + 4 which is 27.
∴
