Giải thích các bước giải:

Ta có:

$\tan\widehat{CBD}=\dfrac{CD}{BC}\to BC=\dfrac{CD}{\tan\widehat{CBD}}=\dfrac{CD}{\tan48^o}$

$\tan\widehat{CAD}=\dfrac{CD}{AC}\to AC=\dfrac{CD}{\tan\widehat{CAD}}=\dfrac{CD}{\tan63^o}$

$AB=BC-AC= \dfrac{CD}{\tan48^o}-\dfrac{CD}{\tan63^o}=CD\cdot (\dfrac1{\tan48^o}-\dfrac1{\tan63^o})$

$\to CD\cdot (\dfrac1{\tan48^o}-\dfrac1{\tan63^o})=24$

$\to CD=\dfrac{24}{\dfrac1{\tan48^o}-\dfrac1{\tan63^o}}$

$\to CD\approx 61.4$