Exercice 13 p. 246 Exercice 14 p. 246 Exercice 17 p. 246 c) On ne

b
P
b
G
b
R
c
M
b
A
cos
b
B=AB
BC
b
D
cos
b
B=BD
BE
cos
b
B
cos
[
P CJ =P C
JC
cos
[
CF P =P F
F C
cos
[
F IP =P I
IF
cos
[
CJP =J P
JC

[
EF G cos
[
EF G =EF
EG
cos
[
EF G =4
8
[
EF G = cos−1(4
8) = 60◦
[
EF G = 60◦.
cos
[
ACB =95
320
[
ACB = cos−1(95
320 ) = 72,7◦72,7◦>70◦
\
KML = cos−1(4
6,5) = 52◦
[
BCA = cos−1(3
4) = 41◦
cos
[
P OT

cos
\
RME =M E
RM
cos
\
RME =24
32
\
RME cos−1(24
32 ) = 41◦
cos
[
BAC =AC
AB
cos 32 = 6
AB
cos 32
1=6 AB
AB ×cos 32 = 6 ×1
AB ×cos 32 = 6
AB =6
cos 32 =

\
MOB = 60◦
\
MBO = 30◦
180◦
\
MOB +
\
MBO +
\
OMB = 180
\
OMB = 180−60−30 = 90
\
MOB = 60◦
cos
\
MOB =OM
OB cos 60 = OM 80
cos 60
1=OM 80
OM ×1 = 80 ×cos 60
OM = 80 ×cos 60 = 40