Aequals 4 pi r squared solve for r squared

If i have 20$ and i gave 5$ away how much i got

Astudent draws two parabolas both parabolas cross the x axis at (-4,0) and (6,0) the y intercept of the first parabolas is (0,-12). the y intercept of the second parabola is (0,-24) what is the positive difference between the a values for the two functions that describe the parabolas

David leaves his house to go to school. he walks 200 meters west and 300 meters north. how far is david from his original starting point?