Answer:
[tex]\boxed{3:1}[/tex]
Step-by-step explanation:
Similar triangles are those whose shape is the same, but they don't necessarily have the same size. However, the corresponding sides of the triangles are in the same length ratio. In this exercise, we know all the sides of triangle ΔABC and an only side of the triangle ΔRST. To find the scale factor, we must compute the following:
[tex]\frac{AB}{RS}=\frac{18}{6}=3 \\ \\ Scale \ factor \\ \boxed{3:1}[/tex]
Finally, the other sides of the tingle ΔRST can be found by dividing each side of triangle ΔABC by 3 as follows:
[tex]ST=\frac{15}{3}=5 \\ \\ RT=\frac{9}{3}=3[/tex]
