Matlab area of triangle question

I'm a newbie to Matlab and have been struggling on this question.

Write a user-defined MATLAB function that determines the area of a triangle when the lengths of the sides are given. For the function name and arguments use [area] = triangle (a, b, c). Of triangle with the following sides:

• a. a = 10, b = 15, c = 7.
• b. a = 6, b = 8, c = 10.
• c. a = 200, b = 75, c = 250.

What I have written but is probably entirely incorrect.

a = [10 6 200];
b = [15 8 75];
c = [7 10 250];
[area] = triangle(a, b, c)
s = (a+b+c)/2;
area = sqrt(s*(s-a)*(s-b)*(s-c));
disp(area);

A line to check if the value's will work in the Heron's formula is not necessary.

Answer 1

[David Goodmanson]

Hello Bob, The good thing is that you are doing this with vectors of values rather than using for loops. Vectorized code is generally better and easier. Suppose you temporarily don't make a function yet, and put a % in front of the [area] = .... line so as to comment it out. The problem right now is that the multiplications you want to do are term-by-term, i.e. the first entry of s times the first entry of (s-a), etc. For that you use .* :

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

and the lines of code run as is. For the function, create and save an mfile like

function [area] =  triangle(a,b,c)
  % do stuff
end

After that you can define a,b,c and use

x = triangle(a,b,c)

where x is any convenient variable name.

[bob saget]

Thank you! It worked. Posting my corrected answer for anybody coming from Google or anywhere else.

a = [10 6 200];
b = [15 8 75];
c = [7 10 250];
%[area] = triangle(a, b, c);
s = (a+b+c)./2;
area = sqrt(s.*(s-a).*(s-b).*(s-c));
fprintf('The areas in order are %.2f\n', area);

Answer 2

[Image Analyst]

I think you're getting all those a, b, and c's confused. It helps to rename them to something descriptive:

function test_triangle_area_function
clc;    % Clear the command window.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
aSides = [10 6 200];
bSides = [15 8 75];
cSides = [7 10 250];
for tri = 1 : length(aSides)
  area = triangle(aSides(tri), bSides(tri), cSides(tri));
  fprintf('Triangle %d: a = %d, b = %d, c = %d, area = %f\n', ...
    tri, aSides(tri), bSides(tri), cSides(tri), area);
end

function area = triangle(a, b, c)
s = (a+b+c)/2;
area = sqrt(s*(s-a)*(s-b)*(s-c));

Answer 3

[Tefo Sheila]

The area of a triangle with sides having the lengths a, b and c is given by the formula A=√(s(s-a)(s-b)(s-a)) where s=(a+b+c)/2. Use MATLAB to a script program called AreaTriScript that calculate the area of triangle having the lengths a,b and c.The program allows user to enter tye values a,b and c through the keyboard using input ( ) command.include the title and comments in your program

Use the program to calculate the area of triangle with sides of lengths (i) a=5cm,b=12cm,c=13cm (ii) a=8cm,b=3cm,c=9cm.Compare your answer with that obtained using the formula A=½ x base x height.

[Image Analyst]

@Tefo Sheila this does not answer @bob saget's question. This looks like your homework question that uses slightly different side length values. I gave a full solution in my answer above.

Since this looks like your homework problem, if you have any questions after reviewing my Answer then ask your instructor or read the link below to get started:

How do I get help on homework questions on MATLAB Answers? - MATLAB Answers - MATLAB Central

and start your own question with your attempt at code.

Answer 4

[Khalid]

Write a program that takes two sides of a stationary triangle and shows the area and shape of this triangle

[Image Analyst]

Try patch and fill and inputdlg