Python Program to Calculate Area of Triangle

You can calculate the area of a triangle in Python using the formula area = 0.5 * base * height. For example, area = 0.5 * 10 * 5 calculates the area when base is 10 and height is 5.

Examples

Inputbase = 10, height = 5

OutputArea of the triangle is 25.0

Inputbase = 3, height = 4

OutputArea of the triangle is 6.0

Inputbase = 0, height = 5

OutputArea of the triangle is 0.0

How to Think About It

To find the area of a triangle, you need to know its base length and height. The area is half the product of the base and height. So, multiply base and height, then divide by 2 to get the area.

Algorithm

1

Get the base length from the user

2

Get the height from the user

3

Calculate area by multiplying base and height, then dividing by 2

4

Display the calculated area

Code

python

base = float(input('Enter the base of the triangle: '))
height = float(input('Enter the height of the triangle: '))
area = 0.5 * base * height
print('Area of the triangle is', area)

Output

Enter the base of the triangle: 10
Enter the height of the triangle: 5
Area of the triangle is 25.0

Dry Run

Let's trace the example where base = 10 and height = 5 through the code

1

Input base

User enters base = 10

2

Input height

User enters height = 5

3

Calculate area

area = 0.5 * 10 * 5 = 25.0

4

Print result

Output: Area of the triangle is 25.0

Step	Variable	Value
1	base	10
2	height	5
3	area	25.0

Why This Works

Step 1: Get inputs

We ask the user to enter the base and height, converting them to numbers with float() so we can do math.

Step 2: Calculate area

We use the formula 0.5 * base * height because the area of a triangle is half the product of its base and height.

Step 3: Show output

We print the result so the user can see the area calculated.

Alternative Approaches

Using Heron's formula

python

a = float(input('Enter side a: '))
b = float(input('Enter side b: '))
c = float(input('Enter side c: '))
s = (a + b + c) / 2
area = (s * (s - a) * (s - b) * (s - c)) ** 0.5
print('Area of the triangle is', area)

This method calculates area using all three sides, useful when height is unknown but sides are known.

Using base and height as integers

python

base = int(input('Enter base: '))
height = int(input('Enter height: '))
area = 0.5 * base * height
print(f'Area of the triangle is {area}')

This uses integer inputs and f-string for output, simpler but less flexible for decimal values.

Complexity: O(1) time, O(1) space

Time Complexity

The calculation involves a fixed number of arithmetic operations, so it runs in constant time.

Space Complexity

Only a few variables are used to store inputs and the result, so space usage is constant.

Which Approach is Fastest?

Both base-height formula and Heron's formula run in constant time, but base-height is simpler and faster since it uses fewer operations.

Approach	Time	Space	Best For
Base and Height Formula	O(1)	O(1)	When base and height are known
Heron's Formula	O(1)	O(1)	When all three sides are known