developing formulas for triangles and quadrilaterals answers
y_3 + x_3 y_4 + x_4 y_1 - (y_1 x_2 + y_2 x_3 + y_3 x_4 + y_4 x_1) \right| \] This formula, known as the shoelace formula, is derived through algebraic manipulation of coordinate points. The Role of Trigonometry in Developing Formulas