Réponse:

a) 3,4cm b)80cm c) 12cm d) 10,3cm

Explications étape par étape:

a) cosCAB = BA / CA

cos(33) = 4 / CA

DF = 4 x cos(33)

DF = 3,4cm

b) tanHIG = GH / HI

tan(85) = GH / 7

GH = 7 x tan(85)

GH = 80cm

c) cosFED = DE/DF

cos(60) = 6/DF

DF = 6 / cos(60)

DF = 12cm

d) sinLKJ = LK / JL

sin(17) = 3 / JL

JL = 3 / sin(17)

JL = 10,3cm