Đáp án:
Giải thích các bước giải:
ta có : $\dfrac{1}{2}a=$ $\dfrac{2}{3}b=$ $\dfrac{3}{4}c$
$\dfrac{a}{2}=$ $\dfrac{b}{\dfrac{3}{2}}=$ $\dfrac{c}{\dfrac{4}{3}}$
$=\dfrac{b-c}{\dfrac{3}{2}-\dfrac{4}{3}}$
$=\dfrac{15}{\dfrac{1}{6}}=90$
$⇔\left[\begin{array}{ccc}a=90.2=180\\b=90.\dfrac{3}{2}=135\\c=90.\dfrac{4}{3} =120\end{array}\right]$