32)
HC = BC - AD = 48 - 27 = 21
cos (angle C) = HC / CD = 21 / 75
angle C = 73,7°
sin (angle C) = HD / DC
HD = sin (angle C)* DC sin (73,7) * 75 = 72°
aire = 27 * 72 + ( 21 * 72 ) / 2 = 1944 + 756 = 2700 m^2 = 27 ares
33)
AB^2 = AC^2 + BC^2
AC^2 = AB^2 - BC^2 = 81 + 51.84 = 29,16
AC = 5.4
AI^2= IC^2 + AC^2 = 3.6^2 + 5.4^2 = 42.12
AI = 6.5
BJ^2= CJ^2 + BC^2 = 2,7^2 + 7,2^2 = 59.13
AI = 7.7
