Enter three side lengths: get area, perimeter, triangle type and a right-angle check.
With Heron's formula: compute the semi-perimeter s = (a+b+c)/2, then area = sqrt(s(s-a)(s-b)(s-c)). No height needed.
If all three sides are equal it is equilateral, if exactly two are equal it is isosceles, otherwise scalene. It also checks whether a squared plus b squared equals c squared to flag a right triangle.
If any side is longer than or equal to the sum of the other two, no triangle exists and the tool says so (the triangle inequality).