Python Program to find Area Of a Triangle

How to write Python Program to find Area Of a Triangle, Perimeter of a Triangle and Semi Perimeter of a Triangle with example. Before we step into the Python Program to find Area Of a Triangle, Let see the definitions and formulas behind Perimeter and Area Of a Triangle.

Area Of a Triangle

If we know the length of three sides of a triangle then we can calculate the area of a triangle using Heron’s Formula

Area of a Triangle = √(s*(s-a)*(s-b)*(s-c))

Where s = (a + b + c )/ 2 (Here s = semi perimeter and a, b, c are the three sides of a triangle)

Perimeter of a Triangle = a + b + c

Python Program to find Area of a Triangle & Perimeter of a Triangle

This Python program allows the user to enter three sides of the triangle. Using those values we will calculate the Perimeter of a triangle, Semi Perimeter of a triangle and then Area of a Triangle.

# Python Program to find Area of a Triangle

a = float(input('Please Enter the First side of a Triangle: '))
b = float(input('Please Enter the Second side of a Triangle: '))
c = float(input('Please Enter the Third side of a Triangle: '))

# calculate the Perimeter
Perimeter = a + b + c

# calculate the semi-perimeter
s = (a + b + c) / 2

# calculate the area
Area = (s*(s-a)*(s-b)*(s-c)) ** 0.5

print("\n The Perimeter of Traiangle = %.2f" %Perimeter);
print(" The Semi Perimeter of Traiangle = %.2f" %s);
print(" The Area of a Triangle is %0.2f" %Area)

OUTPUT

ANALYSIS

Following statements will allow the User to enter the three sides of the triangle a, b, c.

a = float(input('Please Enter the First side of a Triangle: '))
b = float(input('Please Enter the Second side of a Triangle: '))
c = float(input('Please Enter the Third side of a Triangle: '))

Next, Calculating the Perimeter of Triangle using the formula P = a+b+c.

# calculate the Perimeter
Perimeter = a + b + c

Next, Calculating the semi perimeter using the formula (a+b+c)/2. Although we can write semi perimeter = (Perimeter/2) but we want show the formula behind. That is why we used standard formula

s = (a + b + c) / 2

Calculating the Area of a triangle using Heron’s Formula:

(s*(s-a)*(s-b)*(s-c)) ** 0.5

Python Program to find Area of a Triangle using functions

This program allows the user to enter three sides of the triangle. We will pass those three values to the function arguments to calculate the area of a triangle.

# Python Program to find Area of a Triangle using Functions

import math

def Area_of_Triangle(a, b, c):
    
    # calculate the Perimeter
    Perimeter = a + b + c
    # calculate the semi-perimeter
    s = (a + b + c) / 2

    # calculate the area
    Area = math.sqrt((s*(s-a)*(s-b)*(s-c)))

    print("\n The Perimeter of Traiangle = %.2f" %Perimeter);
    print(" The Semi Perimeter of Traiangle = %.2f" %s);
    print(" The Area of a Triangle is %0.2f" %Area)

Area_of_Triangle(6, 7, 8)

OUTPUT

ANALYSIS

First, We imported the math library using the following statement. This will allow us to use the mathematical functions like math.sqrt function

import math

Step 2: Next, We defined the function with three arguments using def keyword. It means, User will enter the three sides of the triangle a, b, c.

Step 3: Calculating the Area of a triangle using Heron’s Formula: sqrt(s*(s-a)*(s-b)*(s-c)); (sqrt() is the mathematical function inside the math library, which is used to calculate the square root.

NOTE: Please be careful while placing the open and close brackets, it may change the entire calculation if you place it wrong