for area: (A=pi×r^2) your diameter is 7.5 so you divide that by 2 to get your radius. and the radius is 3.75. then you are going to do 3.75^2 to get 14.1 then you are going to multiply 14.1 by pi to get 44.18
for circumference: (2×pi×r) you are going to take the same radius for the area and simply multiply that by pi (3.14) to get 11.78, then you are going to multiply 11.78×2 and that equals 23.56
