Answer:
(1) Each side of triangle A is changed by a factor of 1/2.
(2) The unknown side length in triangle B has a measure of 7.5 units.
Step-by-step explanation:
It is given that Alejandro reduced triangle A proportionally.
It means triangle A and B are similar and their corresponding sides are proportional.
[tex]\text{Scale factor}=\frac{\text{Side length of image}}{\text{Corresponding side length of primage}}[/tex]
From the given figure it is clear that the side of length 12 units is reduce to 6 units.
[tex]\text{Scale factor}=\frac{6}{12}[/tex]
[tex]\text{Scale factor}=\frac{1}{2}[/tex]
Each side of triangle A is changed by a factor of 1/2.
Let the unknown side of triangle B be x.
[tex]\frac{x}{15}=\frac{1}{2}[/tex]
On cross multiplication we get
[tex]2x=15[/tex]
Divide both sides by 2.
[tex]x=7.5[/tex]
Therefore, the unknown side length in triangle B has a measure of 7.5 units.