A scalene triangle is a triangle where all three sides have different lengths. Unlike an equilateral triangle (where all sides match) or an isosceles triangle (where two sides match), a scalene triangle has no equal sides at all. Each side is its own length, which usually means each of the three angles inside is different too.

When you're working on geometry problems, recognizing a scalene triangle matters because you can't use the shortcuts that work with more symmetrical triangles. Each side and angle needs to be measured or calculated separately.

You might draw a scalene triangle by picking three lengths that can form a triangle: say 3 inches, 5 inches, and 7 inches. Connect them, and you'll have a lopsided triangle where nothing matches. It's one common type of triangle in the real world. Look at the triangular supports in a bridge or the sail on a boat, and you'll often find scalene triangles doing the work of holding things up or catching the wind.