Calculate the area of geometry

I have a difficult problem and I need help, "Write a function to calculate the area and perimeter of shapes: triangle, rectangle, circle?"

[Walter Roberson]

Please read http://www.mathworks.com/matlabcentral/answers/6200-tutorial-how-to-ask-a-question-on-answers-and-get-a-fast-answer

[Minh]

@Walter Rober i read it , i just want to say this problem is too difficult for me , i want to combine the same script but i can only do one idea calculate the area of each shape.

Answer 1

[Walter Roberson]

The first thing you need to do is decide how the user is going to represent the specific shape for calculation purposes.

• are you going to have them input coordinates of each point?
• are you going to have them input parameters such as height and width of the square, or radius of the circle?
• are you going to have them input side lengths for the triangle? Side Angle Side ? From one side and two angles https://sciencing.com/calculate-triangle-one-side-given-8464316.html ? From three angles?
• are you going to have the user draw the shape on the screen?

Once you have made the decision about representation, we can assist you in what user interface calls to make to fetch the input.

[Minh]

@Walter Roberson

My purpose:

- point coordinates will be randomly selected.

- requires manual input of parameters such as the height and width of the square or the radius of the circle.

- the area of the triangle will be calculated from the perimeter of the triangle.

Answer 2

[Sam Chak]

Hi @Minh

If you know the point coordinates of the geometry, perhaps you can explore the area() function.

x = [0 2 1.5];
y = [0 0 1];
pgon = polyshape(x, y);
plot(pgon)
axis equal

A = area(pgon)          % Area

A = 1

P = perimeter(pgon)     % Perimeter

P = 4.9208

[Minh]

@Sam Chakthanks for your contribution

Answer 3

[Minh]

#include<stdio.h>

#include<math.h>

main(){

int choice;

printf("Enter\n1 to find area of Triangle\n2 for finding area of Circle\n3 for finding area of Rectangle\n");

scanf("%d",&choice);

switch(choice) {

case 1: {

int a,b,c;

float s,area;

printf("Enter sides of triangle\n");

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

s=(float)(a+b+c)/2;

area=(float)(sqrt(s*(s-a)*(s-b)*(s-c)));

printf("Area of Triangle is %f\n",area);

break;

}

case 2: {

float len,breadth,area;

printf("Enter Length and Breadth of Rectangle\n");

scanf("%f %f",&len,&breadth);

area=(float)len*breadth;

printf("Area of Rectangle is %f\n",area);

break;

}

case 3: {

float radius,area;

printf("Enter Radius of Circle\n");

scanf("%f",&radius);

area=(float)3.14159*radius*radius;

printf("Area of Circle %f\n",area);

break;