Learn Pythagoras' Theorem part 1: Squares
Learn to use the relationship
Teacher version
Interactive lesson part 2
Interactive lesson all in one
Explain how to calculate the area of the largest square.
Pythagoras' Theorem says that if we construct squares on the three sides of a right triangle, the two smaller squares will fit perfectly into the largest square. The largest square lies opposite the right angle.
On the next applet, move the green and yellow pieces so that they fit perfectly into the largest square.
Change the triangle around to make sure it works on all kinds of right-triangles.
For every adding fact, there are two subtracting facts.
Use 'subtract' to calculate the area of the third square when the area of the largest square and one of the smaller squares is given.
On the next applet, you need to decide whether to add or subtract.
Explain how you know whether to add the two given areas or to subtract.
On the next applet, all the squares are blue.
The triangle rotates around.
Be sure to identify the longest side before deciding whether to add or subtract.
The longest side lies opposite the right angle.
The name of the longest side on a right-angled triangle is the 'hypotenuse'.