What grade does 5th graders be in?

Idon’t understand 8. plz ! we are finding the area of polygons. thx in advance!

Type the correct answer in each box. use = 3.14 and if necessary, round your answers to the nearest hundredth. the area of the largest cross section of a sphere and the circumference of the sphere are in the ratio 4: 1. cm. the area of the largest cross section is about the radius of the sphere is cm. the circumference of the sphere is about cm2. the volume of the sphere is about cm?

This is a major archaeological site that was once a regional center to the mayan empire in ancient mesoamerica.