11. The area of the circle is pi×r^2 so pi×6^2= 113.1cm^2 rounded to 1 d.p.
The area of the rectangle is 4×4=16cm^2
So to find out the area of the shaded region, do 113.1-16= 97.1cm^2
12. The area of a rectangle is l×w so 40×18=720cm^2
The area of the triangle is 1/2(l×w) so 1/2(9×12)=1/2(108)= 54cm^2
So to find out the area of the shaded region, do 720-54= 666cm^2
