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bonsoir



CB//CA = CD/CE
13/3 = 12/CE

13 CE = 3 x 12
13 Ce = 36
CE = 2.8 cm arrondis

PQ/PR = PT/PS = QT/RS

7/PS = 5/8
5 PS = 56
PS = 11.2
donc TS = 11.2 - 7 = 4.2 cm