Réponse :

1)TE = BR-VT

TE = 13-9,6=3,4cm

2) BVT rectangle en V

BT²=BV²+VT²

BT²= 7,2²+9,6²

BT = √144=12cm

3) (BR)//(TE)

thales

NT/NB=TE/BR

NT/NT+12 = 3,4/13

13NT = 3,4(NT+12)

13NT =3,4NT+40,8

13NT-3,4NT = 40,8

NT = 4,25cm