от Гост » 03 Апр 2017, 13:47
[tex]S=\frac{d_1.d_2}{2}=\frac{d_1.\frac{3}{4}d_1}{2}=\frac{3d_1^2}{8}=48 \Rightarrow d_1^2=128 \Rightarrow d_2=\frac{9d_1^2}{16}=72[/tex]
[tex]\Rightarrow a^2=\frac{d_1^2+d_2^2}{4}=\frac{128+72}{4}=50 \Rightarrow a=5\sqrt{2}[/tex]