Length, ABC
$$\vert ABC \vert =½ · \sqrt{b^2+16 · a^2}+…$$
$$\frac{b^2}{8 · a} · \ln{\Bigg(\frac{4 · a + \sqrt{b^2+16 · a^2}}{b}}\Bigg)$$
Enter lengths
(Use decimal separator ".")
Length, a
Length, b
Length, ABC