Question

Alex draws a rectangle of dimensions 3 cm in width and 6 cm in length. He wants to rescale it by a scale factor of $\frac{4}{3}$, What are the dimensions of the new rectangle?

• A. Width $=4$ cm and Length $=10$ cm
• B. Width $=4$ cm and Length $=8$ cm
• C. Width $=5$ cm and Length $=8$ cm
• D. Width $=5$ cm and Length $=10$ cm

Answer 1

The correct option is B Width $=4$ cm and Length $=8$ cm

$\underset{–}{\text{Dimensions of original rectangle :}}$

Width $=3$ cm and Length $=6$ cm
Scale factor $=\frac{4}{3}$

Concept: Dimension of a new rectangle = Dimension of a original rectangle $\times$ Scale factor

Hence, Dimension of the new rectangle $=\frac{4}{3}$ of dimension of the original rectangle




$\text{Width of new rectangle}=3\times \frac{4}{3}=4\text{cm}$

$\text{Length of new rectangle}=6\times \frac{4}{3}=8\text{cm}$

(b) is the correct option