The area of the figure is the sum of areas of all rectangles forming the figure.
Looking at the figure there are 4 rectangles, 3 rectangles of dimensions 3 m and 4m and 1 rectangle of dimensions 3 m and 7 m.
$\therefore$ Area = (3 $\times$ 4)+ (3 $\times$ 4) + (3 $\times$ 4) + (3 $\times$ 7) + (3 $\times$ 3)
                          = 12 + 12 + 12 +21 + 9
                          = 66 sq. units