I need help pleaseee❤️

Circle a has a diameter of 7 inches, a circumference of 21.98 inches, and an area of 38.465 square inches. the diameter of circle b is 6 inches, the circumference is 18.84 inches, and the area is 28.26 square inches. part a: using the formula for circumference, solve for the value of pi for each circle. (4 points) part b: use the formula for area and solve for the value of pi for each circle. (4 points)

Find the area of the region that is inside r=3cos(theta) and outside r=2-cos(theta). sketch the curves.

Erik buys 2.5 pounds of cashews. if each pound of cashews costs $7.70, how much will he pay for the cashews?