Question

A triangular array of dominoes has one domino in the first row, two dominoes in the second row, three dominoes in the third row, and so on. If there are 15 rows, how many dominoes are in the array? (FIGURE CANNOT COPY)

Name: Problem 70, Chapter 10: Intermediate Algebra
Uploaded: 2020-06-23T10:43:03-08:00
Duration: 1 min 3 s
Channel: Ankit Gupta
Description: A triangular array of dominoes has one domino in the first row, two dominoes in the second row, three dominoes in the third row, and so on. If there are 15 rows, how many dominoes are in the array? (FIGURE CANNOT COPY)

   A triangular array of dominoes has one domino in the first row, two dominoes in the second row, three dominoes in the third row, and so on. If there are 15 rows, how many dominoes are in the array?
(FIGURE CANNOT COPY)

Intermediate Algebra

Julie Miller, Molly… 5th Edition

Chapter 10, Problem 70

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Solved by Expert Ankit Gupta

06/23/2020

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This forms an arithmetic sequence with a common difference of 1. Show more…

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A triangular array of dominoes has one domino in the first row, two dominoes in the second row, three dominoes in the third row, and so on. If there are 15 rows, how many dominoes are in the array? (FIGURE CANNOT COPY)

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Key Concepts

Arithmetic Series

An arithmetic series is the sum of a sequence of numbers that increase by a constant difference between consecutive terms. In this context, the sequence 1, 2, 3, ..., n forms an arithmetic series, and its sum is found using a well-established formula.

Triangular Numbers

Triangular numbers are a sequence of numbers where each number represents the total number of dots that can form an equilateral triangle. They are equivalent to the sum of the first n natural numbers and are used to model arrangements in triangular arrays.

Summation Formula

The summation formula n(n+1)/2 for the first n natural numbers provides a quick and efficient method to calculate the sum without individually adding each term. This formula is essential when dealing with problems that require the summing of sequential numbers arranged in a triangular pattern.

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