Final answer:
To calculate the percentage error in Joey's heart rate measurement, we find the difference between the measured value and the actual value, divide it by the actual value, and multiply by 100. The percentage error is 10%.
Step-by-step explanation:
To calculate the percentage error, we first need to find the difference between the measured value and the actual value. In this case, Joey measured his heart rate as 99 beats per minute when his actual heart rate was 90 beats per minute. The difference is 99 - 90 = 9 beats per minute.
Next, we divide the difference by the actual value and multiply it by 100 to get the percentage error. So, the percentage error is (9 / 90) × 100 = 10%.
Therefore, the percentage error in Joey's heart rate measurement is 10% (option A).