Final answer:
The area of a circle with a radius of 1 kilometer is 3.14 km², but it should be expressed as 3 km² because the radius has only one significant figure.
Step-by-step explanation:
To calculate the area of a circle with a given radius, you can use the formula A = πr², where 'A' represents the area, 'π' (pi) is approximately 3.14, and 'r' is the radius of the circle. Since we are given that the radius (r) is 1 kilometer, our calculation for the area becomes A = 3.14 × (1 km)². When we perform this calculation, it results in A = 3.14 km². Because the radius is given with only one significant figure, our final answer should also be reported with one significant figure, so the area of the circle is 3 km².