This page will help you calculate the side lengths of a triangle given the aspect ratio and the hypotenuse length.
It is useful for calculating the width and height of a computer display.
Last active
September 24, 2020 18:15
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Triangle solver given aspect ratio and hypotenuse length
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| <!doctype html> | |
| <html> | |
| <head> | |
| <meta charset="utf-8"> | |
| <title>Triangle solver given aspect ratio and hypotenuse length</title> | |
| <style> | |
| body { | |
| font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; | |
| } | |
| label { | |
| display: block; | |
| width: auto; | |
| text-align: right; | |
| } | |
| button { | |
| display: block; | |
| width: auto; | |
| margin: auto; | |
| } | |
| table { | |
| border: 1px solid black; | |
| } | |
| .inputerror { | |
| color: red; | |
| } | |
| .inputnoerror { | |
| color: black; | |
| } | |
| </style> | |
| </head> | |
| <body> | |
| <p> | |
| Given a right triangle with aspect ratio Ra : Rb and hypotenuse length C, | |
| calculate the side lengths A and B. | |
| </p> | |
| <p> | |
| This can help you calculate a screen's width and height. Put the monitor size (ex. 24") as C, | |
| and the aspect ratio as Ra : Rb (ex. 16:9). | |
| </p> | |
| <table> | |
| <tr><td><label>Ra:</label></td><td><input type="number" class="inputnoerror" onchange="form_update()" id="input_Ra" min="1" value="16"></td></tr> | |
| <tr><td><label>Rb:</label></td><td><input type="number" class="inputnoerror" onchange="form_update()" id="input_Rb" min="1" value="9"></td></tr> | |
| <tr><td><label>C: </label></td><td><input type="number" class="inputnoerror" onchange="form_update()" id="input_C" min="1" value="24"></td></tr> | |
| <tr><td colspan="2"><button onclick="form_update()">Calculate</button></td></tr> | |
| <tr><td><label>A: </label></td><td><input type="number" id="output_A" disabled></td></tr> | |
| <tr><td><label>B: </label></td><td><input type="number" id="output_B" disabled></td></tr> | |
| </table> | |
| <script> | |
| function form_setError(elem, err) { | |
| elem.className = err ? "inputerror" : "inputnoerror"; | |
| } | |
| function form_getInputs() { | |
| const input_Ra = document.getElementById('input_Ra'); | |
| const input_Rb = document.getElementById('input_Rb'); | |
| const input_C = document.getElementById('input_C'); | |
| const Ra = parseFloat(input_Ra.value); | |
| const Rb = parseFloat(input_Rb.value); | |
| const C = parseFloat(input_C.value); | |
| let err = false; | |
| if (isNaN(Ra) || Ra <= 0) { form_setError(input_Ra, true); err = true; } else { form_setError(input_Ra, false); } | |
| if (isNaN(Rb) || Rb <= 0) { form_setError(input_Rb, true); err = true; } else { form_setError(input_Rb, false); } | |
| if (isNaN(C) || C <= 0) { form_setError(input_C, true); err = true; } else { form_setError(input_C, false); } | |
| if (err) return undefined; | |
| return { | |
| Ra: Ra, | |
| Rb: Rb, | |
| C: C, | |
| }; | |
| } | |
| function form_setOutputs(vals) { | |
| const output_A = document.getElementById('output_A'); | |
| const output_B = document.getElementById('output_B'); | |
| let A = ""; | |
| let B = ""; | |
| if (vals) { | |
| A = vals.A; | |
| B = vals.B; | |
| } | |
| output_A.value = A; | |
| output_B.value = B; | |
| } | |
| function form_update() { | |
| const inputs = form_getInputs(); | |
| if (!inputs) { | |
| form_setOutputs(undefined); | |
| return; | |
| } | |
| const Ra = inputs.Ra; | |
| const Rb = inputs.Rb; | |
| const C = inputs.C; | |
| const R = Ra/Rb; | |
| const B = C * Math.sqrt(1 / (R*R + 1)); | |
| const A = B*R; | |
| form_setOutputs({ | |
| A: Math.round(A * 1000) / 1000, | |
| B: Math.round(B * 1000) / 1000, | |
| }); | |
| } | |
| form_update(); | |
| </script> | |
| </body> | |
| </html> |
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| MIT License | |
| Copyright (c) 2020 Cooper Harasyn | |
| Permission is hereby granted, free of charge, to any person obtaining a copy | |
| of this software and associated documentation files (the "Software"), to deal | |
| in the Software without restriction, including without limitation the rights | |
| to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
| copies of the Software, and to permit persons to whom the Software is | |
| furnished to do so, subject to the following conditions: | |
| The above copyright notice and this permission notice shall be included in all | |
| copies or substantial portions of the Software. | |
| THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
| IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
| FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
| AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
| LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
| OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
| SOFTWARE. |
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