The outside circle has a radius of 10 cm; therefore, the area of the whole logo is: pi·102 or 100pi
The outside of the blue region is a circle of radius 7 cm; therefore its area is: pi·72 or 49pi
The inside of the blue region is a circle of radius 4 cm; therefore its area is: pi·42 or 16pi
The blue area is the outside region minus the inside region: 49pi - 16pi = 33pi
The percentage of the logo that is blue is: 33pi / 100pi = 33/100 = 0.33 = 33%