Question

A triangle ABC is enlarged, about the point O as centre of enlargement, and the scale factor is 3. Find OA, if OA'= 6 cm.

• A. 2 cm
• B. 3 cm
• C. 4 cm
• D. none of the above

Answer 1

The correct option is A 2 cm

$△ABC$ is enlarged to $△A^{\prime }{B}^{\prime }{C}^{\prime }$,
Thus, $\frac{O{A}^{\prime }}{OA}=3$
$\Rightarrow \frac{6}{OA}=3$
$\Rightarrow OA=\frac{6}{3}$
$\Rightarrow OA=2$ cm