Question

Please help/ Image below!

Answer 1

The figure is composed of squares,
the area of each square is equal to the side-length squared

to convert square millimetres to square centimetres

[mm]^2 = [0.1cm]^2
= 0.1^2 [cm]^2
= 0.01 [cm]^2

so 1 [cm]^2 = 100 [mm]^2