C Program to find area of triangle square circle or rectangle using switch statement

Program

#include<stdio.h>
#define PI 3.147
void main()
{
	float radius, length, breadth;
	float base, height, area;
	int choice;
	printf("Enter\n");
	printf("1. To find area of triangle\n2. To find area of Square\n");
	printf("3. To find area of circle\n4. To find area of rectangle\n");
	scanf("%d",&choice);
	switch(choice)
	{
		case 1:
			printf("Enter base and height of a triangle\n");
			scanf("%f %f", &base, &height);
			area = (1.0/2) * base * height;
			printf("Area of Triangle:\t%f\n", area);
			break;
		case 2:
			printf("Enter length of a Square\n");
			scanf("%f", &length);
			area = length * length;
			printf("Area of Square:\t%f\n", area);
			break;
		case 3:
			printf("Enter the radius of a Circle\n");
			scanf("%f", &radius);
			area = PI * radius * radius;
			printf("Area of Circle:\t%f\n", area);
			break;
		case 4:
			printf("Enter the length and breadth of a Rectangle\n");
			scanf("%f %f", &length, &breadth);
			area = length * breadth;
			printf("Area of Rectangle:\t%f\n", area);
			break;
		default:
			printf("Invalid Choice\n");
	}
}

Output 1

Enter
1. To find area of triangle
2. To find area of square
3. To find area of circle
4. To find area of rectangle
1
Enter base & height of a triangle
4
5
Area of Triangle:	10.000000

Output 2

Enter
1. To find area of triangle
2. To find area of square
3. To find area of circle
4. To find area of rectangle
2
Enter length of a square
4
Area of Square:	16.000000

Output 3

Enter
1. To find area of triangle
2. To find area of Square
3. To find area of circle
4. To find area of rectangle
3
Enter the radius of a Circle
5
Area of Circle:	78.675003

Output 4

Enter
1. To find area of triangle
2. To find area of Square
3. To find area of circle
4. To find area of rectangle
4
Enter the length and breadth of a Rectangle
5
6
Area of Rectangle:	30.000000