we have been asked to find the sum of the series

As we know that a geometric series has a constant ratio "r" and it is defined as

The first term of the series is 
Geometric series sum formula is

Plugin the values we get

On simplification we get

Hence the sum of the given series is
The congruence theorem that can be used is: B. ASA
<h3>What is the ASA Congruence Theorem?</h3>
If we have two triangles that have two pairs of corresponding congruent angles (e.g. ∠LGH ≅ ∠HKJ and ∠LHG ≅ ∠KHJ), and a pair of corresponding congruent sides (e.g. GH ≅ HK), the triangles are said to be congruent triangles by the ASA congruence theorem.
Therefore, triangles GHL and KHL in the image given are congruent triangles by the ASA congruence theorem.
Learn more about the ASA congruence theorem on:
brainly.com/question/2398724
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Answer:
It is called the constant ratio.