the rate of change for the function f(t)=2.6t+17.8 can be used to estimate the yearly sales of cotton goods; in billikns of dollars, as a function of time; in years, measured from 1975

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)