▭ 矩形对角线计算器（含面积与周长）Rectangle Diagonal Calculator (with Area and Perimeter)

使用说明与常见问题How-to & FAQ

「矩形对角线计算器（含面积与周长）」是什么？What is the Rectangle Diagonal Calculator (with Area and Perimeter) tool?

矩形对角线 d = √(l² + w²)，并给出面积 lw 与周长 2(l+w)。边长须大于 0。本地处理。Rectangle diagonal d = √(l² + w²), plus area lw and perimeter 2(l+w). Sides must be greater than 0. Processed locally.

如何使用「矩形对角线计算器（含面积与周长）」？How do I use the Rectangle Diagonal Calculator (with Area and Perimeter) tool?

在「矩形对角线计算器（含面积与周长）」中，填写「长」、「宽」等参数，结果会随输入实时计算并显示在下方。In the Rectangle Diagonal Calculator (with Area and Perimeter): Fill in "Length", "Width"; results are recalculated instantly as you type.

正方形呢？What about a square?

长宽相等时就是正方形：对角线 = 边长 × √2。When length equals width it is a square: diagonal = side × √2.

长方体的体对角线？What about a box space diagonal?

本页是平面矩形。长方体对角线是 √(l²+w²+h²)。This page is a 2D rectangle. A rectangular box uses √(l²+w²+h²).

能举个计算实例吗？Can you show a worked example?

例如在「矩形对角线计算器（含面积与周长）」中填 长 = 8，宽 = 6，结果区显示：对角线：10；面积：48；周长：28For example, entering Length = 8, Width = 6 in the Rectangle Diagonal Calculator (with Area and Perimeter) gives: Diagonal: 10; Area: 48; Perimeter: 28

哪些输入会被检查？Which inputs are validated?

「矩形对角线计算器（含面积与周长）」会检查这些输入——「长」：必须填写，须大于 0且不大于 1,000,000,000,000,000；「宽」：必须填写，须大于 0且不大于 1,000,000,000,000,000；绝对值超过 10¹⁵ 的数也会被拒绝。不符合时结果区显示具体提示，不会给出数字。The Rectangle Diagonal Calculator (with Area and Perimeter) checks its inputs — "Length": required, must be more than 0 and at most 1,000,000,000,000,000; "Width": required, must be more than 0 and at most 1,000,000,000,000,000; numbers above 10¹⁵ in absolute value are rejected too. When a value fails, the result area names the problem instead of showing a number.

有哪些选项可以调整？What options can I adjust?

「矩形对角线计算器（含面积与周长）」的设置：「长」默认 8；「宽」默认 6。每次生成结果都按当前设置处理。Settings in the Rectangle Diagonal Calculator (with Area and Perimeter) — "Length" default 8; "Width" default 6. The result always uses the current settings.

计算精度如何？How precise are the results?

「矩形对角线计算器（含面积与周长）」使用 JavaScript 双精度浮点数（约 15–16 位有效数字）；极大或极小的数值可能存在精度误差。The Rectangle Diagonal Calculator (with Area and Perimeter) uses double-precision floating point (about 15–16 significant digits); very large or very small values may lose precision.

「矩形对角线计算器（含面积与周长）」免费吗？需要注册吗？Is the Rectangle Diagonal Calculator (with Area and Perimeter) free? Do I need an account?

「矩形对角线计算器（含面积与周长）」完全免费，无需注册或安装，打开网页即可使用，手机和电脑都能用；输入的内容只在你的浏览器本地处理。The Rectangle Diagonal Calculator (with Area and Perimeter) is completely free with no sign-up or install and works on phones and desktops; what you enter is processed only in your browser.