-2.5(-3+4n+8) in expanded form of the expression

Consider the proof. given: segment ab is parallel to line de. prove: what is the missing statement in step 5?

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)

What is the point of inflection for the function f(x)=2cos4x on the interval (0, pi/2)