Module 4 · Creating multi-parameter functions · Lesson 2 of 5

Triangles

Here's a function with three parameters — three side lengths — and a real question to answer: do these sides actually form a triangle? The rule is the triangle inequality: each side must be shorter than the sum of the other two. All three checks have to hold.

That “all three must hold” is exactly what and is for. The function combines the three comparisons into one Boolean and returns it — a clean True or False.

Once you know the sides do make a triangle, a second three-parameter function can find its area with Heron's formula. Notice the pattern again: check first, then compute — two small functions, each with a single clear job.

From here the problems get more mathematical — and introduce a pattern of their own. First up: factorials.