math de 3 eme merci de m aider c urgent

bonsoir

Te = 13 - 9.6 = 3.4 cm
Bt² = 7.2 ² + 9.6² = 144
BT = √144
Bt = 12 cm

TB/TN = TV/TE = Bv/NE

12/TN = 9.6/3.4
9.6 Tn = 3.4 x 12
9.6 Tn = 40.8
Tn = 4.5 environ