Final answer:
To calculate the area of a cross section of a pie, use the formula A = πr² and subtract the area of the hole. The radius is half the diameter of each part. Calculate the area using the formulas given and subtract to find the cross-sectional area.
Step-by-step explanation:
To calculate the area of a cross section of a pie, we need to calculate the area of the full pie and subtract the area of the hole.
The area of a circle is given by the formula A = πr², where r is the radius. In this case, the diameter of the pie is 4.78 km, so the radius is half of that, or 2.39 km.
The area of the full pie is therefore A = π(2.39 km)². To calculate the area of the hole, we use the same formula, but with a radius of half the diameter of the hole, which is 1.89 cm.
The area of the hole is then A = π(1.89 cm) ². Finally, we subtract the area of the hole from the area of the full pie to get the area of the cross section.