( au carré = ^2 )
a) BC^2 = AB^2 + AC^2
BC^2 = 3,6^2 + 2,7^2
BC^2 = 12,96 + 7,29
BC^2 = 20,25
BC = (Racine carré) 20,25
BC = 4,5 cm
b) BC^2 = BC^2 + DC^2
11,7^2 = 4,5^2 + DC^2
DC^2 = 11,7^2 - 4,5^2
DC^2 = 136,80 - 20,25
DC^2 = 116,55
DC = (Racine carré) 116,55
DC = ( environ ) 12,90 cm
