Pythagoras Lab
An interactive Pythagorean theorem. Drag a right triangle and watch the Pythagoras area squares on each side — a², b², and c² — update together. The a²+b²=c² visual stays true as you drag. The right angle stays fixed. Free, no login, ready for a classroom projector.
Who·Grades 7–9 on a projector or iPad
Teacher tip
Project this page and tap Full screen. Explore opens on a 3–4–5 triangle. Drag a corner: the squares are the areas, and 9 + 16 = 25 stays true. Tap Show why — the big square splits into two rectangles, one matching each leg. Open Triples and tap 5–12–13, then 8–15–17. Missing side hides one length. Add the areas, or drag the free leg until the hypotenuse matches, then tap Check. One idea fits in five minutes.
Drag a corner. The right angle stays put, and the squares show the areas.
a
3
b
4
c
5
a²
9
b²
16
c²
25
Leg a 3, leg b 4, hypotenuse c 5. Areas 9, 16, and 25. 9 + 16 = 25. The areas match. The 3–4–5 triple.
The right angle stays fixed. Drag the other corners, or use plus and minus. Arrows move a focused corner. Whole numbers snaps the legs. Show why splits the big square into the two leg areas. Escape clears.