bonjour
aire du rectangle = 9 ( b + 3) = 9 b + 27
aire du triangle = [ 9 ( b + 15)]/2 = (9 b + 135) / 2 = 4.5 b + 67.5
9 b + 27 = 4.5 b + 67.5
9 b - 4.5 b = 67.5 - 27
4.5 b = 40.5
b = 9
rectangle = 9 * ( 9 + 3) = 9 *12 = 108 cm²
triangle = ( 9 * 24) / 2 = 108
