Cant figure it out pls help

Scale factor = 2

This is the same as writing

===============================================

Explanation:

Focus on the left sides of each triangle. They correspond to one another. Note how RS represents the first two letters of RST; while MN represents the first two letters of MNO. We can see the order matters.

To find the scale factor, we divide MN over RS to get

MN/RS = 6/3 = 2

Therefore, the sides of triangle MNO are 2 times longer compared to the sides of triangle RST.

------------------------

Extra info:

If you want to find x, then you would solve the following

MN/RS = ON/TS

6/3 = x/5.5

6*5.5 = 3x

33 = 3x

3x = 33

x = 33/3

x = 11

or we could simply multiply ST = 5.5 by the scale factor 2 getting 5.5*2 = 11, which is the length of segment ON.