what is the scale factor from figure a to figure b

Answer:
[tex]\frac{1}{2}[/tex]
Step-by-step explanation:
The scale factor is the ratio of corresponding sides , B to A
The right vertical side of B is 2 units
The right vertical side of A is 4 units
scale factor = [tex]\frac{2}{4}[/tex] = [tex]\frac{1}{2}[/tex]