a+b+c+d
a = b:3 => b = 3×a
c = a
c = d:4 =>d = 4×c
d - c = 27
a |___|
b |___|___|___|
c |___|
d |___|___|___|___|
4 segmente egale - 1 segment egal = 3 segmente egale = 27
27 : 3 = 9 ( un segment)
a = 9
b = 3×9 = 27
c = 9
d = 4×9 = 36
V. 36-9 = 27
9 + 27 +9 +36 = 81 ( suma)