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

Given, Area of circle = 36 cm²
Area of rectangle = $\frac{\text{Area of circle}}{6}$....(given)
                              = $\frac{36}{6}$ 
                              = 6 cm²
$\because$ Area of rectangle = length x breadth 
$\Rightarrow$ 6 = length x 1

So, length = 6 cm

Area of square = side $\times$ side
$\therefore$ side $\times$ side = 4 cm²
$\Rightarrow$ side = 2 cm
Now,
Length of the bigger rectangle = 5 $\times$ 2
                                                    = 10 cm
Breadth of the bigger rectangle = 2 $\times$ 2
                                                      = 4 cm
$\therefore$ Perimeter of the bigger rectangle
= 2( Length + Breadth)
= 2(10 + 4)
= 28 cm

On dividing the figure into squares and rectangle, it will look like:

The are of figure is sum of areas of square 1 and  rectangles 2 and 3.

=(1 x 1) + ( 4 x 5 ) + (3 x 5 ) 
= 1 + 20 + 15 
= 36 sq. units