Work out the diagonal of a rectangle when you need a corner-to-corner distance for screens, layouts, framing checks, or geometry.
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diagonal = sqrt(length^2 + width^2)The diagonal forms the hypotenuse of a right triangle built from the two side lengths.
This is the same principle used in 3-4-5 layout checks.
Open this calculator for cases where a small arithmetic slip would otherwise force a full restart around cube face diagonal.
Next: rectangle area.
Calculate rectangle perimeter when you need border length for trim, fencing, framing, edging, or basic geometry problems.
Because a rectangle diagonal creates a right triangle with the rectangle sides.
Yes, if you know the visible width and height of the display area.