**Program Abstraction:***This article contains a simple C program to find the area of rectangle, circle and triangle.*

Finding the area of rectangle, circle, or triangle is one of common questions in C practical examination. Finding the area of circle, rectangle and triangle may in a same question or question may ask you find area of anyone of above shape.

This is a C program to find area of a rectangle, circle and triangle in a same program. You can separate this program as your needs.

ØManually we can find the area of a rectangle by using equation: Area = Breadth * Length.

ØAlso we can find the area of a circle by using equation:

Area = 3.14 * (radius)^{2}

ØAlso we can find the area of a triangle by using equation:

IF:

a = length of first side

b = length of second side

c = length of third side

s= (a + b+ c)/2

Area = sqrt(s*(s-a)*(s-b)*(s-c))

-where sqrt stands for square root

**Program Code:**

#include <stdio.h>

#include <conio.h>

#include <stdlib.h>

#include <math.h>

void main()

{

int a,b,c,r, rectarea;

float circlearea, s1,s2,s3;

float s,triarea2;

clrscr();

printf("n Three Choices");

printf("n…………………….n 1- rectanglen 2- circlen 3- triangle");

printf("n Enter your choice :");

scanf("%d",&c);

switch(c)

{

case 1:

printf("n Enter breadth and length of rectangle:");

scanf("%d%d",&a,&b);

rectarea = a * b;

printf("Area of rectangle with breadth %d and length %d is %d units",a,b, rectarea);

break;

case 2:

printf("n Enter the radius of circle:");

scanf("%d",&r);

circlearea = 3.14 * r * r;

printf("Area of triangle with radius %d is %f units ",r, circlearea);

break;

case 3:

printf("n Enter the three side of triangle:n");

scanf("%f%f%f",&s1,&s2,&s3);

s = (s1 + s2 + s3)/2;

triarea2 =sqrt(s *((s - s1) * (s - s2) * (s - s3)));

printf("Area of triangle is %f",triarea2);

break;

default:

printf("Invalid choice");

}

getch();

}

**Sample output for finding area of a rectangle with breadth and length 5 and 10 respectively:**

Enter the breadth and length of rectangle:

5

10

Area of rectangle breadth 5 and length 10 is 50 units

Sample output for finding area of a triangle with the length of sides as 4, 5, and 6

Enter the length of the 3 sides of triangle:

4

5

6

Area of triangle is 9.921

**Sample output for finding area of a circle with radius 3:**

Enter the radius of circle : 3

Area of triangle with radius 3 is 28.260000 units

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