February 7, 2012
25 one inch squares make a square 5 inches on a side.
That is exactly the same size as a 16 by 16 LEGO plate.
25 is also 16 plus 9.
Note: 52 = 32 + 42
a2 + b2 = c2 for a right triangle.
You can see with LEGO Friends ruler
that a 3, 4, 5 triangle is a right triangle.
A right triangle made on the floor with sides of 3 feet and 4 feet has a hypotenuse of 30 plus 30 inches.
60 inches is 5 feet.
This is a 3, 4, 5 right triangle.
The class has been studying Egypt.
When the Nile flooded it washed away the property makers.
Long ago Egyptian knew how to mark off a right angle using 3, 4, 5 triangle.
The class made many triangles
They checked to see if they were right triangles.
It was fun to multiply the lengths of the sides by themselves and add the two squares
then square the hypotenuse and see if it was the same.
