A state border is thousands of miles long (some of them). Meters would be too small of a measurement. Centimeters is even smaller. So the answer is B. Because this uses the least amount of numbers.
Since it's an equilateral triangle, all of the angles are the same. Since its perimeter we just need to add. So 3.5+3.5+3.5= 10.5 So the answer is 10.5
