Question

$△ABC$ is enlarged, about the point $O$ as the centre of enlargement, and the scale factor is $3$. Find $BC$, if $B^{\prime }{C}^{\prime }=15$ $cm$.

Answer 1

Every side of $△ABC$ will be enlarged by 3 to give sides of $△A^{\prime }{B}^{\prime }{C}^{\prime }$

$\therefore 3\times BC=B^{\prime }{C}^{\prime }$

$⟹BC=\frac{15}{3}=5cm$