a circular garden has a diameter of 12 feet. what is the best approximation for the circumference of the garden? use 3.14 to approximation pi

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