A geometric sequence is where you multiply by a constant number to get the next number.
An arithmetic sequence is where you add by a constant number to get the next number.
In the sequence 2, 10, 50, 250, the difference between the numbers are different, but when you multiply each number by 5, you get the next number.
This means that this is a geometric sequence.
The next term would be 250 x 5 which is 1250.
