Proof of the Pythagorean Theorem Without Math

The Pythagorean Theorem states that for any triangle with one angle at 90 degrees, the area of the squares of the two smaller sides adds up to be equal to the area of the square of the largest side.
Pythagorean Theorem
FIGURE 1: The Pythagorean Theorem: c2 = a2 + b2

Figure 2 shows how the four triangles can be moved to prove that: c2 = a2 + b2
Pythagorean Theorem
FIGURE 2: Proof of the Pythagorean Theorem
Above Image By William B. Faulk

In construction, it is common to use the Pythagorean Theorem to check that an angle is 90 degrees. For example, mark off 4 units in the vertical, 3 units in the horizontal and then check that the third side is 5 units. If so, the angle is 90 degrees.
FIGURE 3: Using a 345 triangle to check a 90 degree angle
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