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A figure has (42) rows, and the (r)th row has (r) dots. How many dots will there be in total?
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Answer and explanation
Correct answer: (903)
Total dots are (S_{42}=\frac{42\times43}{2}=903). Having (r) dots in the (r)th row is the sum of natural numbers.
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What is the correct answer to this question?
(903)
Why is this the correct answer?
Total dots are (S_{42}=\frac{42\times43}{2}=903). Having (r) dots in the (r)th row is the sum of natural numbers.
Which subject and chapter does this question cover?
This is a Class 9 Mathematics question. Chapter: Sequences and Progressions. Topic: Sum of first n natural numbers.
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