Answer:
c
Step-by-step explanation:
Answer:
The correct answer would be 15.5 or C.
The answer is D because all the other go against the triangle inequality theorem. which states that the sum of the side lengths of any 2 sides of a triangle must exceed the length of the third side<span>
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As we can see that common difference is increasing to one more digit after every term
so it means
a21 = 231
