[tex]Pp*H=V /:H\\Pp=\frac{V}H\\Pp=\frac{480cm^3}{10cm}=48cm^2\\\\Pp=ab\\a:b = > 3:4\\\frac{a}b=\frac34 /*b\\a=\frac34b\\\\\frac34b*b=48cm^2 /*\frac43\\b^2=64cm^2\\b=8cm\\a=\frac34*8cm=6cm\\\\d^2=a^2+b^2\\d^2=36cm^2+64cm^2\\d^2=100cm^2\\d=10cm\\\\D^2=d^2+H^2\\D^2=100cm^2+100cm^2\\D^2=200cm^2\\D=\sqrt{200cm^2}=\sqrt{4*2*25}cm=2*5\sqrt2cm=10\sqrt2cm\\\\\\sin\alpha=\frac{H}D=\frac{10cm}{10\sqrt2cm}=\frac{1}{\sqrt2}=\frac{\sqrt2}2\\\alpha=45st[/tex]
