we must divide the figure on parts
we have 3 areas
firts will calculate the green triangle
the formula is

where the height is 15ft and the base 19-4=15ft
so replacing

Second will calculate the red rectange
the formula is

where the height 25 and the base 4

Third will calculate the yellog triangle
th formula is

where b is 4ft and the height 29-25=4ft

Finally to calculate the total Area add all areas

so, the total area of the polygon is 220.5 square feet