Question

find the missing side length, in units, in the scaled copy.
original | scaled copy
5 | 15
10 |
(there is an image showing an original rectangle with length 10 and height 5, and a scaled copy rectangle with height 15 and unknown length ?)

Explanation:

Step1: Find the scale factor

The original height is 5 and the scaled copy height is 15. So the scale factor is $\frac{15}{5}=3$.

Step2: Apply the scale factor to the original length

The original length is 10. Multiply by the scale factor: $10\times3 = 30$.

Answer:

30