bonjour,
si angle A =52
angle C=70
alors
angle B=58
triangle rectangle AHC
Cos A= 20/hc
Cos 52°=0.61
0.61=20/HC
HC=32
triangle rectangle BHC
tangente B=HC/HB
tangente58°=1.6
1.6=32/HB
HB=20
triangle rectangle BPC
angle C=70
d'où
angle B=20
Cos B=HB/BC
Cos20°=0.52
0.52=20/BC
BC=38
Sin C=BP/BC
Sin 70°=0.9
0.9=BP/38
BP=34