$(10$ points$)$ Calculate the Area of a Circle. Write a program in $C$ to calculate the area of a circle. The radius of the circle should be entered by the user. Use the float datape for the radius and area, and define PI as a constant $($#define PI $3\mathrm{.}14159).$

$(10$ points$)$ Convert Seconds to Hours, Minutes, and Seconds. Create a C program where the user inputs a number of seconds. The program should convert this value into hours, minutes, and seconds. Use appropriate data types and ensure that the result is displayed in the format $"$HH hours MM minutes SS seconds."