Answer:
488281250 is the Twelfth
Explanation:
The geometric sequence is multiplying by 5
2, 10, 50,
2 times 5 is 10 (First)
10 times 5 is 50 (Second)
50 times 5 is 250 (Third)
250 times 5 is 1250 (Fourth)
1250 times 5 is 6250 (Fifth)
6250 times 5 is 31250 (Sixth)
31250 times 5 is 156250 (Seventh)
156250 times 5 is 781250 (Eighth)
781250 times 5 is 3906250 (Ninth)
3906250 times 5 is 19531250 (Tenth)
19531250 times 5 is 97656250 (Eleventh)
97656250 times 5 is 488281250 (Twelfth)