\[\boxed{\mathbf{486.ОК\ ГДЗ - домашка\ на}\ 5}\]
\[Рисунок\ по\ условию\ задачи:\]
\[\textbf{а)}\ \text{AB} = 5;\text{AC} = 13;\text{AD} - ?:\]
\[\text{AB} =\]
\[= \text{CD}\ (по\ свойству\ прямоугольника);\]
\[AC^{2} = CD^{2} + AD^{2}\]
\[AD^{2} = AC^{2} - CD^{2} = 169 - 25 =\]
\[= 144\]
\[\text{AD} = 12.\]
\[\textbf{б)}\ \text{CD} = 1,5;\text{AC} = 2,5;\text{BC} - ?:\]
\[BC^{2} = AC^{2} - CD^{2} =\]
\[= 6,25 - 2,25 = 4\]
\[\text{BC} = 2.\]
\[\textbf{в)}\ \text{BD} = 17;\text{BC} = 15;\text{CD} - ?:\]
\[CD^{2} = BD^{2} - BC^{2} =\]
\[= 289 - 225 = 64\]
\[\text{CD} = 8.\]