$\textbf{Bài 2:}$
$\text{Ta có: $\widehat{xOy}$ + $\widehat{xOy'}$ = $180^o$}$
$\text{Số đo góc $\widehat{xOy}$ là:}$
$\text{ $\widehat{xOy}$ = $180^o$ : (2 + 3) . 2 = $72^o$}$
$\text{$\widehat{xOy}$ = $\widehat{xOy'}$ = $72^o$ (đđ)}$
$\text{Vậy $\widehat{x'Oy'}$ = $72^o$}$
$\textbf{Bài 3:}$
$\text{Ta có: $\widehat{xOy}$ + $\widehat{xOy'}$ = $180^o$}$
$\text{Tỉ số số đo của $\widehat{xOy}$ và $\widehat{xOy'}$ 5 : 4}$
$\text{Nên $\widehat{xOy}$ = $\dfrac{5}{4}$$\widehat{xOy'}$}$
$\text{Số đo $\widehat{xOy}$ là:}$
$\text{ $\widehat{xOy}$ = $180^o$ : (5 + 4) . 5 = $100^o$}$
$\text{$\widehat{xOy}$ = $\widehat{x'Oy'}$ = $100^o$ (đđ)}$
$\text{Số đo $\widehat{xOy'}$ là:}$
$\text{ $\widehat{xOy'}$ = $180^o$ - $100^o$ = $80^o$}$
$\text{$\widehat{xOy'}$ = $\widehat{x'Oy}$ = $80^o$ (đđ)}$
$\text{Vậy $\widehat{xOy}$ = $\widehat{x'Oy'}$ = $100^o$}$
$\text{$\widehat{xOy'}$ = $\widehat{x'Oy}$ = $80^o$}$
$\text{HỌC TỐT NHA! ♫•*¨*•.¸¸♪}$
$Thanhnhung_♩$
