{"id":82774,"date":"2025-12-04T11:37:22","date_gmt":"2025-12-04T11:37:22","guid":{"rendered":"https:\/\/www.oreateai.com\/blog\/how-to-find-r-in-geometric-sequence\/"},"modified":"2025-12-04T11:37:22","modified_gmt":"2025-12-04T11:37:22","slug":"how-to-find-r-in-geometric-sequence","status":"publish","type":"post","link":"https:\/\/www.oreateai.com\/blog\/how-to-find-r-in-geometric-sequence\/","title":{"rendered":"How to Find R in Geometric Sequence"},"content":{"rendered":"

Finding the Common Ratio in a Geometric Sequence: A Friendly Guide<\/p>\n

Imagine you\u2019re sitting at your kitchen table, surrounded by an array of colorful fruits. You\u2019ve got apples, bananas, and oranges stacked neatly in front of you. Now picture this: each time you add another layer of fruit to your pile, you’re not just tossing them on haphazardly; instead, there\u2019s a specific pattern guiding how many pieces go into each layer. This is somewhat akin to what happens in a geometric sequence\u2014a mathematical arrangement where each term builds upon the last through multiplication by a constant factor known as the common ratio.<\/p>\n

So how do we find that elusive common ratio (often denoted as "r")? Let\u2019s break it down together.<\/p>\n

First off, let\u2019s clarify what we mean by a geometric sequence. It\u2019s simply a series of numbers where each term after the first is found by multiplying the previous one by r. For example, if our first term (let’s call it ‘a’) is 2 and our common ratio is 3, then our sequence would look like this: 2 (first term), 6 (2 multiplied by 3), 18 (6 multiplied by 3), and so forth\u2014resulting in something like: (2, 6, 18,) and (54).<\/p>\n

Now onto finding r! The formula for calculating the common ratio between terms can be summarized quite succinctly:<\/p>\n[ r = \\frac{\\text{n}^\\text{th} \\text{term}}{\\text{(n -1)}^\\text{th} \\text{term}} ]\n

This means that to find r for any two consecutive terms in your sequence\u2014say from position n to n-1\u2014you simply divide the nth term by its preceding counterpart.<\/p>\n

Let\u2019s take an example straight out of math class. Consider this geometric sequence: (3840,) (960,) (240,) (60,) and finally (15.)<\/p>\n

To discover our common ratio here:<\/p>\n

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  1. \n

    Start with the last number ((15)) divided by its predecessor ((60)):<\/p>\n