Answer:
22,700 ft
Step-by-step explanation:
To convert the units of miles to feet, multiply 4.30 miles by 5280 feet/ 1 mile. This will cancel the units of miles.
3 significant figures means that three non-zero values are in the largest places of your answer. In this case, it is the ten thousands, thousands, and hundreds place that will have non-zero values from your calculation. If your calculation gives values past the hundreds place then round to the lowest place significant figure you'd like. In this case, the actual answer is 22,704 but we round to 22,700.