Specific range of numbers is given, trying to get another number within same range

I'm trying to calculate the width of an HTML element based on the window size.

Here's what I have. These width values (first value) accurately match with the width the HTML element must be (second value). However I need to get a formula for this to be able to set the width of the HTML correctly according to any possible window size.

window width / HTML element width

• 1663 = 1916
• 1221 = 1692
• 1119 = 1641
• 1038 = 1602
• 630 = 1396

• 1500 = ????

• 1400 = ????
• 2000 = ????

I've been staring at this four hours but I just can't wrap my head around it..

Any help would be appreciated.

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All of your equations are false. $1663$ is not the same as $1916$", and the $=$ sign does not mean "corresponds to, in some unspecified context-dependent way". – Henning Makholm Apr 26 '12 at 12:22

Linear regression gives: $m=0.5030755166$ $c=1078.8117490$ with $R^2=0.9999778405$. This gives the desired values as