PK=2c
h=[b]2c[/b]
ОК=2с*sin α
a=2ОК=[i]4*с*sin α [/i]
S_(осн)=a^2=([u]4*с*sin α[/u])^2=16c^2*sin^2 α
S_(бок)=(1/2)*4a*h=2a*h=2*([u]4*с*sin α[/u])*[b]2c[/b]=16c^2*sin α
S_(пол )=S_(бок)+S_(осн)=16c^2*sin α +16c^2*sin^2 α = 16c^2*(1+sin α)*sin α