Okay, we see that there are 10 pieces in the circle - thus, it is our denominator. Next, we see that 9 out of them are coloured in. Therefore, the fraction is 9/10. To express our answer as a percent, we need to divide 9 and 10 to get 0.9. Then, we multiply 0.9 by 100 to get 90%. As a result, your answer is 90%.