Question

Write a C function that calculates the area of a circle when its circumference, c, is given. This function should call a second nested function that returns the radius, r, of the circle, given c. The relevant formulas are r = c/2π and a = πr². Write a C program that accepts the value of the circumference from the user, calculates the radius and area, and displays the calculated values from within the main function. Your program should use the functions written above.

Answer 1

A C program can calculate the area of a circle given the circumference by using a nested function to find the radius and another function to compute the area. The main function prompts for the circumference, calls the helper functions for computations, and displays the result.

Step-by-step explanation:

The subject of this question involves programming in C to calculate the area of a circle given its circumference. To perform this calculation, two formulas are necessary: the radius of a circle (r = c / (2π)) and the area of a circle (a = πr²). Using these formulas, a C function can be created to determine the radius using the circumference, and a second function to calculate the area using the radius. Here is how such a program might be structured:

#include <stdio.h>
#define PI 3.14159

double findRadius(double circumference) {
return circumference / (2 * PI);
}

double calculateArea(double radius) {
return PI * radius * radius;
}

int main() {
double circumference, radius, area;

// Prompt user for circumference
printf("Enter the circumference of the circle: ");
scanf("%lf", &circumference);

// Calculate radius and area using the functions
radius = findRadius(circumference);
area = calculateArea(radius);

// Output the results
printf("The radius of the circle is: %.2lf\\", radius);
printf("The area of the circle is: %.2lf\\", area);

return 0;
}

In the main function, the user is prompted to enter the value of the circumference. The findRadius function calculates the radius, which is passed to the calculateArea function to compute the area. Finally, the calculated radius and area are displayed to the user with two significant figures, consistent with the rules for significant figures.