Explanation:
1) Radius = Half of Diameter
2) Given r = 4 in.
Circumference of Circle =
3) Given r = 5 in.
Area of Circle =
4)Diameter = 2x Radius
Note for questions 2 and 3 I will leave answers in terms of pi as the question did not specify to leave the answer as what. You can use your calculator to evaluate them if needed.