Written: August 22, 2026
Two common classroom versions exist: area from base and height (½·b·h), and area from three sides with Heron’s formula. Both are short and good input-validation practice.
Base and height
base = float(input("Base: "))
height = float(input("Height: "))
area = 0.5 * base * height
print(f"Area = {area:.2f}")Heron’s formula
import math
a = float(input("Side a: "))
b = float(input("Side b: "))
c = float(input("Side c: "))
s = (a + b + c) / 2
area = math.sqrt(s * (s - a) * (s - b) * (s - c))
print(f"Area = {area:.2f}")Reject inputs that cannot form a triangle (triangle inequality) before calling sqrt, or you will hit a math domain error.
Keep learning
If this walkthrough on python triangle area helped, open the code again and change one input or assumption. Small experiments beat rereading the same example.
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