Question

A triangle ABC is enlarged, about the point O as centre of enlargement, and the scale factor is 3. Find A'B', if AB = 4cm.

• A. 12 cm
• B. 14 cm
• C. 22 cm
• D. none of the above

Answer 1

The correct option is A 12 cm

$△ABC$ is enlarged to $△A^{\prime }{B}^{\prime }{C}^{\prime }$,
Thus, $\frac{A^{\prime }{B}^{\prime }}{AB}=3$
$\Rightarrow \frac{A^{\prime }{B}^{\prime }}{4}=3$
$\to A^{\prime }{B}^{\prime }=4\times 3$
$\Rightarrow A^{\prime }{B}^{\prime }=12$ cm