To find the area of a circle, you need to know its radius or diameter. If 'b' represents the radius of the circle, you can use the formula for the area of a circle:
Area = π * (radius)^2
If 'b' is the radius and it's equal to 20, then the area of the circle is:
Area = π * (20)^2 ≈ 1256.64 square units (rounded to two decimal places).