(a) Scale factor.
To find the scale factor, we just have to divide two corresponding sides between the rectangles, let's divide 15 by 10.
[tex]\frac{15}{10}=1.5[/tex]
Therefore, the scale factor is 1.5.
(b) The missing side length.
To find the missing side length, we just have to divide the scale factor with 24 because that's the corresponding side. Notice that we have to divide because the missing side length is smaller than 24.
[tex]\frac{24}{1.5}=16[/tex]
Therefore, the missing side length is 16 units.
