For an oblique triangle with points LTR where L is lower left, T top (apex), and R lower right:
Let C be the exact center point of baseline LR.
If imaginary line goes from point T down to point C, then what is angle TCR? The lengths of triangle's sides are known: LT LR TR The triangle's 3 angles at L, T, R can be derived using Law of Cosines.
But how to get angle TCR?