Answer:
The percent of error in her measurement is 1.3%
Step-by-step explanation:
we know that
The circumference of a circle is equal to

where
D is the diameter
we have

assume

substitute
----> This value represent the 100% (theoretical value)
Find the difference between the theoretical value and the measured value
Find the percentage by proportion

I have completed the 1st one and have attached it.
X = 9
Move the 1 over to make it 3x = 28. The. 28/3 equals 9