Answer this please.

What is the circumference of a circle with an area of 50.24 cm²?

The weight of a radioactive isotope was 96 grams at the start of an experiment. after one hour, the weight of the isotope was half of its initial weight. after two hours, the weight of the isotope was half of its weight the previous hour. if this pattern continues, which of the following graphs represents the weight of the radioactive isotope over time? a. graph w b. graph x c. graph y d. graph z

Ahovercraft takes off from a platform. its height (in meters), xx seconds after takeoff, is modeled by: h(x)=-2x^2+20x+48h(x)=−2x 2 +20x+48 what is the maximum height that the hovercraft will reach?