Answer :
[tex]\frac{5}{6}\ \times\ 210cm=5\ \times\ 35=175cm\\\\Answer:Darren's\ height\ is\ 175cm.[/tex]
[tex]210 \ cm \cdot \frac{5}{6}\ =35\ \cdot \ 5=175 \ cm\\\\Answer: \ \ \ Darren's \ height \ is\ 175cm.[/tex]