Question

$△ABC$ is enlarged, about the point $O$ as the centre of enlargement, and the scale factor is $3$. State the value of $\frac{O{B}^{\prime }}{OB}$

Answer 1

Every length related to $△ABC$ will be enlarged by 3 to give corresponding increased lengths of $△A^{\prime }{B}^{\prime }{C}^{\prime }$

$\therefore 3\times OB=O{B}^{\prime }$

$⟹\frac{O{B}^{\prime }}{OB}=3$