In this circle the area of the sector COD is 50.24

The area of the sector is equal to half of the square of the radius times the opening of the sector (theta). Basing on the figure, the angle of sector COD is 90 degrees. So,

Area of sector = 50.24 = (1/2) * (r^2) (theta)

The theta should be expressed in radians. So, we convert 90 degrees to radians:

90 degrees (pi rad/180 degrees) = pi/2

Thus,

50.42 = (1/2) * (r^2) * (pi/2)

r^2 = 64.2

r = 8.01 units

Thus, the radius of the sector is 8.1 units.