Question Number 66979 by Mr Jor last updated on 21/Aug/19
Commented by Mr Jor last updated on 21/Aug/19
$${In}\:{the}\:{figure}\:{above},\:{OC}=\mathrm{3}{CA}\:{and} \\ $$$${OD}=\mathrm{3}{DB}.{By}\:{taking}\:\boldsymbol{{OA}}=\boldsymbol{{a}},\boldsymbol{{OB}} \\ $$$$=\boldsymbol{{b}},{show}\:{that}\:{CB}//{AB}. \\ $$