a - krawedz podstawy
b - krawedz boczna
[tex]Pp=a^2\\Pp=16^2=256[/tex]
Sciana boczna jest trojkat rownoramienny, zatem:
[tex](\frac12a)^2+h^2=b^2\\8^2+h^2=20^2\\64+h^2=400 /-64\\h^2=336\\h=\sqrt{336}=\sqrt{16*21}=4\sqrt{21}[/tex]
[tex]Pb=\frac{ah}2\\Pb=\frac{16*4\sqrt{21}}2=16*2\sqrt{21}=32\sqrt{21}[/tex]
[tex]Pc=Pp+4Pb\\Pc=256+4*32\sqrt{21}=256+128\sqrt{21}[/tex]
