Foundation and Higher · Pythagoras

Why does
a² + b² = c²
actually work?

let me show you.
Pythagoras —
Right-Angled
Only works when one angle
is exactly 90°.
worked example

Pythagoras'
Theorem

1. Right-angled triangle — sides a, b, c.
2. Square the two shorter sides.
3. 5² + 12² = 25 + 144 = 169.
4. So c² = 169  →  c = √169.
✓ c = 13
a a = 5 b b = 12 a² 25 b² 144 169 c²
the only rule that matters
a² + b² = c²
works on right-angled triangles.
No right angle? Use
trig or the cosine rule.
The
Maths Habit
Download The Maths Habit app
to test your knowledge
0.0s
0:00 / 0:00