Answer:
[tex]A = 336[/tex] [tex]m^{2}[/tex]
Step-by-step explanation:
Using the formulas
[tex]A=\sqrt{s(s-a)(s-b)(s-c)}[/tex]
[tex]s=\frac{a+b+c}{2}[/tex]
Solving for [tex]A[/tex]
[tex]A=\frac{1}{4} \sqrt{-a^{4}+2(ab)^{2} +2(ac)^{2} -b^{4} +2(bc)^{2}-c^{4} }[/tex]
[tex]=\frac{1}{4} *\sqrt{-42^{4} +2*(42*34)^{2}+2*(42*20)^{2} -34^{4} +2*(34*20)^{2} -20^{4} }[/tex]
[tex]=336m^{2}[/tex]
