How do you calculate area of a scalene triangle?

Answer 1

Suppose the sides are of length x, y and z units.

Let s = (x + y + z)/2

Then Area = sqrt[s*(s - x)*(s - y)*(s - z)] square units.

Alternatively,

the angle between the lines with lengths y and z is

arccos[(y^2 + z^2 - x^2)/(2*y*z)] = theta, say.

And then area = 0.5*y*z*sin(theta).