Question

original\tscaled copy
4\t?
10\t5
?
what is the scale factor from the original figure to the scaled copy?

Explanation:

Step1: Recall scale - factor formula

The scale factor $k$ from the original to the scaled - copy is given by $k=\frac{\text{scaled - copy length}}{\text{original length}}$.

Step2: Choose a pair of corresponding sides

We can use the pair of lengths where the original length is 10 and the scaled - copy length is 5.

Step3: Calculate the scale factor

$k = \frac{5}{10}=\frac{1}{2}=0.5$

Answer:

$0.5$