Answer:
5.5
Step-by-step explanation:
[tex]\frac{1}{2} |x_{1} (y_{2} -y_{3}) + x_{2} (y_{3} -y_{1} ) + x_{3} (y_{1}- y_{2} ) |\\= \frac{1}{2} \times |5(4-5) + 8 (5-2) + 4(2-4) |\\=\frac{1}{2} \times |-5 +24 + -8 |\\=\frac{1}{2} \times 11\\= 5.5[/tex]
