For every right triangle: a² + b² = c² — the two small squares add up to the big one
Change leg a and leg b with − and +. Watch the two small squares' areas add up to the big square.
Leg a
Leg b
a² (red square)
9
b² (blue square)
16
c² (big square)
25
3² + 4² = 9 + 16 = 25
Hypotenuse c
√25 = 5
✓ the two small squares fill the big square exactly