Find the area of a triangle, assume that you don't know the formula of area of any other figure.
The Attempt at a Solution
Well, i was trying to figure out how to find the area of a triangle out of nowhere, but could not get it. I want to know how it was formulated for the very first time. Please help me out (remember that you cannot use any other area formula) . You can use basic calculus, but not very advanced one.