Find the missing length. The triangles in each pair are similar. Please explain.

Answer:
RT = 121
Explanation:
Since ∆RST ~ ∆RCB, their corresponding side lengths of both triangles are proportional to each other.
Therefore:
RS/RC = RT/RB
RS = 132
RC = 36
RT = ?
RB = 33
Plug in the values into the equation
132/36 = RT/33
Cross multiply
36*RT = 33*132
36*RT = 4,356
Divide both sides by 36
RT = 4,356/36
RT = 121