Answer:
A ≈ 28.5
Step-by-step explanation:
a, b, c
P = a + b + c
Semiperimeter s = [tex]\frac{a+b+c}{2}[/tex]
A = [tex]\sqrt{s(s-a)(s-b)(s-c)}[/tex]
~~~~~~~~~~~~~~~
[tex]P_{ABC}[/tex] = 4.3 + 2.89 + 6.81 = 14
s = 14 ÷ 2 = 7
[tex]A_{ABC}[/tex] = [tex]\sqrt{7(7-4.3)(7-2.89)(7-6.81)}[/tex] = √14.75901 ≈ 3.84
[tex]P_{BCD}[/tex] = 8.59 + 7.58 + 6.81 = 22.98
s = 22.98 ÷ 2 = 11.49
[tex]A_{BCD}[/tex] = [tex]\sqrt{11.49(11.49-8.59)(11.49-7.58)(11.49-6.81)}[/tex] = √609.7343148 ≈ 24.6928
[tex]A_{ABCD}[/tex] = 3.84 + 24.6928 ≈ 28.5
