To find the area of B:
divide B into section like the attached figure:
the area of triangle 1 = 0.5 * 1 * 5 = 2.5 square units
the area of triangle 2 = 0.5 * 2 * 2 = 2 square units
the area of triangle 4 = 0.5 * 2 * 2 = 2 square units
the are of rectangle 3 = 3 * 4 = 12
so, the area of Figure B = 2.5 + 2 + 2 + 12 = 18.5 squre units
To find the area of A
We can divide the area into two shapes
square and triangle
i will attach a figure for good explanation :
so, the area of the square = 3 * 3 = 9 square units
and the area of the triangle = 0.5 * base * height = 0.5 * 1 * 3 = 1.5 square units
So, the area of A = 9 + 1.5 = 10.5 square units.