Annular section simple implementation in C

annularsection.c

#define _USE_MATH_DEFINES
#include <math.h>

double annsec_MomentOfInertia (double insideD, double outsideD) {
	return M_PI * (pow(outsideD, 4) - pow(insideD, 4)) / 64;
}

double annsec_PolarMomentOfInertia (double insideD, double outsideD) {
	return M_PI * (pow(outsideD, 4) - pow(insideD, 4)) / 32;
}

double annsec_Area (double insideD, double outsideD) {
	return M_PI * (pow(outsideD, 2) - pow(insideD, 2)) / 4;
}

annularsection.h

#pragma once

double annsec_MomentOfInertia (double insideD, double outsideD);

double annsec_PolarMomentOfInertia (double insideD, double outsideD);

double annsec_Area (double insideD, double outsideD);

main.c

#include <stdio.h>
#include "annularsection.h"

int main(void) {
	double insideD, outsideD;
	double area, moi, polarmoi;

	printf("Enter inside diameter:\n");
	while(scanf("%lf",&insideD) != 1) {
		printf("Wrong input, please retry:\n");
	}

	printf("Enter outside diameter:\n");
	while(scanf("%lf",&outsideD) != 1) {
		printf("Wrong input, please retry:\n");
	}

	area = annsec_Area(insideD, outsideD);
	moi = annsec_MomentOfInertia(insideD, outsideD);
	polarmoi = annsec_PolarMomentOfInertia(insideD, outsideD);

	printf("Area: %lf\n", area);
	printf("Moment of inertia: %lf\n", moi);
	printf("Polar moment of inertia: %lf\n", polarmoi);
}