12) F

To solve this question, we need to use the similarity rules.

You need to identify that triangles PQT and PRS are similar.

 QT   =       RS
 PT         PT + TS

 0.3    =       1.5
 PT          PT + 1.8

0.3 (PT + 1.8) = 1.5PT
0.3PT + 0.54 = 1.5PT
0.54 = 1.2PT
PT = 0.54 ÷ 1.2 = 0.45

PS = PT + TS
PS = 0.45 + 1.80 = 2.25 cm