ГДЗ по математике 5 класс Мерзляк ФГОС Задание 416

 

\[\boxed{\ \mathbf{416\ (416)}.\ Еуроки\ - \ ДЗ\ без\ мороки}\]

\[\angle ABC = 72^{0};\]

\[BD - биссектриса\ \angle ABC;\]

\[BE - биссектриса\ \angle ABD.\]

\[\angle CBE = \angle CBD + \angle DBE\]

\[\angle CBD = \angle ABC\ :2 = 72\ :2 =\]

\[= 36^{0}.\]

\[\angle DBE = \angle CBD\ :2 = 36\ :2 =\]

\[= 18^{0}.\]

\[\angle CBE = 36^{0} + 18^{0} = 54^{0}.\]

\[Ответ:54^{0}.\]

\[\boxed{\mathbf{416}\mathbf{\ (382)}.\ Еуроки\ - \ ДЗ\ без\ мороки}\]

\[1)\ (x - 18) - 73 = 39\]

\[x - 18 = 39 + 73\]

\[x = 112 + 15\]

\[x = 130.\]

\[24 + (y - 52) = 81\]

\[y - 52 = 81 - 24\]

\[y = 57 + 52\]

\[y = 109.\]

\[x + y = 130 + 109 = 239.\]

\[2)\ (65 - x) + 14 = 51\]

\[65 - x = 51 - 14\]

\[x = 65 - 37\]

\[x = 28.\]

\[(y + 16) + 37 = 284\]

\[y + 16 = 284 - 37\]

\[y = 247 - 16\]

\[y = 231.\]

\[x + y = 28 + 231 = 259.\]