Final answer:
Explains the concept of a geometric progression and shows how to calculate the sum of the given geometric sequence.
Explanation:
Geometric Progression: The given sequence follows a geometric progression. In a geometric progression, each term is obtained by multiplying the previous term by a constant factor called the common ratio.
Sum of Geometric Progression: To find the sum of the first 9 terms of the geometric progression 4, 20, 100,..., you can use the formula for the sum of n terms in a geometric progression: Sn = a(1 - rn)/(1 - r), where a is the first term, r is the common ratio, and n is the number of terms.
Calculation: In this case, a = 4, r = 5, and n = 9. Plugging these values into the formula will give you the sum of the first 9 terms.
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