The diagram to the right shows the first 3 rows of seating in an amphitheater. The rows are arranged in rings around a central stage.
How many seats are there in the
first row?
second row?
third row?
How many seats will there be in the 9th row?
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In the example above, we see that the number of seats in each row is
We call this a sequence, which simply means a list of numbers in a specific order. Most interesting sequences follow a pattern, for example: