# Thread: How to calculate the reference of numbers?

1. ## How to calculate the reference of numbers?

Is there anyway to calculate the following? As you can see when the first number increases the 2nd number only increases a little bit. I would like to calculate the other numbers with the same reference. Thanks

6.6162 = 2.598
11.2262 = 2.939

9.2362 = ? ( I know is around 2.7 something)
4.9068 = ?
2.7659 = ?

2. ## Re: How to calculate the reference of numbers?

Originally Posted by leosantare
Is there anyway to calculate the following? As you can see when the first number increases the 2nd number only increases a little bit. I would like to calculate the other numbers with the same reference. Thanks

6.6162 = 2.598
11.2262 = 2.939

9.2362 = ? ( I know is around 2.7 something)
4.9068 = ?
2.7659 = ?
You can do a linear interplation/extrapolation.

Just use the point slope formula for a line.

$m=\dfrac {2.939-2.598}{11.2262-6.6162} \approx 0.074$

$y-y_0 = m(x-x_0)$

$(y-2.939) \approx 0.074(x-11.2262)$

$y\approx 0.074 x +2.1082612$

$\begin{pmatrix} 2.7659 &2.313\\ 4.9068 &2.471\\ 6.6162 &2.598\\ 9.2362 &2.792\\ 11.2262 &2.939 \end{pmatrix}$

3. ## Re: How to calculate the reference of numbers?

Originally Posted by leosantare
Is there anyway to calculate the following? As you can see when the first number increases the 2nd number only increases a little bit. I would like to calculate the other numbers with the same reference. Thanks

6.6162 = 2.598
11.2262 = 2.939

9.2362 = ? ( I know is around 2.7 something)
4.9068 = ?
2.7659 = ?
Unfortunately, there are an infinite number of possibly correct answers. If you had more data, you could exclude many possibilities, but no matter how much data you had, you could never be 100% certain of getting the correct answer.

With this little in the way of data, your best guess is to assume a linear relationship.

$\dfrac{y - 2.939}{x - 11.2262} = \dfrac{2.939 - 2.598}{11.2262 - 6.6162} = \dfrac{0.341}{4.61} \implies 4.61y - 13.54879 = 0.341x - 3.8281342 \implies$

$y = \dfrac{0.341x + 13.54879 - 3.8281342}{4.61} = 0.074x + 2.1086.$

Let's check

$0.074 * 6.6162 + 2.1086 \approx 2.598.$ Looks good.

$0.074 * 11.2262 + 2.1086 \approx 2.939.$ Looks good.

So for example $0.074 * 9.2362 + 2.1086 \approx 2.792.$

4. ## Re: How to calculate the reference of numbers?

Wow, that's pretty cool. These equations are much more advanced to me, is this Trigonometry? Although the 2.7659 and 4.9068 are a bit too high. If I provide the smallest and middle values, can you find the relationship of the others more accurately? I'm trying to decide on the number of holes I want on 5 gaskets. The first value represents the bolt hole circle and the second value represents the spacing between the holes, including the curve. I want the spacing to increase slightly in uniform as the bolt hole circle increases in size.

2.7659 = 2.172 @4 holes
4.9068 = ?
6.6162 = 2.598 @8 holes
9.2362 = ?
11.2262 = ?

5. ## Re: How to calculate the reference of numbers?

I used only elementary algebra. However, you mention curves, and the answers supplied so far do not apply to a curve.

Someone may be able to help you with respect to a well-defined curve. However, you will have to describe very carefully what kind of curve you are contemplating. This may take time because math has a very precise vocabulary that most people do not know. So there are significant problems in terms of communication.