Calculations at an equilateral triangle which is bisected through one corner. This is a right triangle with angles of 30, 60 and 90 degrees.
Enter one value and choose the number of decimal places. Then click Calculate.
Formulas:
Catheti (legs), hypotenuse, height and perimeter have the same unit (e.g. meter), the area has this unit squared (e.g. square meter).
The hypotenuse is one of the sides of the original equilateral triangle. The shorter leg is another of its sides, which has been bisected. The third of the original sides has vanished. The longer leg corresponds to the altitude of the equilateral triangle. The altitude, or specifically, the altitude relative to side c, of the half equilateral triangle is calculated using the formulas for right triangles. It measures half the length of the original altitude, which now serves as the longer leg. The perimeter of the half equilateral triangle is just under 79 percent of that of the corresponding equilateral triangle, whereas its area has of course been halved.
Upon bisection, all axes of symmetry of the equilateral triangle are lost, as is its rotational symmetry. The resulting half equilateral triangle possesses no symmetries whatsoever. Much like the equilateral triangle and other regular polygons, the half equilateral triangle is uniquely defined by a single value, from which all its other properties can be calculated.
Two half equilateral triangles can be joined along their hypotenuses to form a rectangle. If one of the two is reflected or flipped over, the pair can instead form a right kite. The side lengths of these two new shapes are a and b, respectively, and their area is of course once again equal to that of the original equilateral triangle. The non-right angles of the right kite measure 60 and 120 degrees.
Cite this page: Rechneronline (2026) - Halved Equilateral Triangle. Retrieved on 2026-06-08 from https://rechneronline.de/pi/half-equilateral-triangle.php