The name Pythagorean theorem came from a Greek mathematician by the named Pythagoras. Pythagoras developed a formula to find the lengths of the sides of any **right triangle**. Pythagoras Discovered that if he treated each side of a right triangle as a square (see figure 1) the two smallest squares areas when added together equal the area of the larger square. The formula is A2 + B2 = C2, this is as simple as one **leg **of a triangle squared plus another leg of a triangle squared equals the **hypotenuse **squared.

In this lesson I will teach you how to use the Pythagorean theorem, I will show where you put it to use and some different ways to use the theorem to find the lengths of legs when given the leg length and the hypotenuse length. I will try my best to explain every step of the way to my fullest and complete answer.

My inspiration for this instructable came from having the interest of finding how formulas work. I take interest especially in the Pythagoras theorem because we use it in lots of every day jobs such as engineering, woodworking and metalworking. I hope I can pass my interests on to you in this lesson.

Prescribed learning outcomes, by learning how the Pythagorean theorem works students will learn how to square, square root, add and subtract, and learn the Pythagoras formula.

Key words...

**Hypotenuse- **In geometry, a hypotenuse is the longest side of a right-angled triangle, the side opposite the right angle.

**Leg**- Either sides of a right triangle that are opposite to the hypotenuse.

**Right triangle**- A triangle that has one corner of a ninety degree angle.

## Step 1: How to use the formula

Lets start with an example. If we know that leg A of the triangle is 3cm and leg B is 4cm the first step is **squaring** our legs. We can do this simply by multiplying one leg by same amount as its self, So therefore we get A = 9 and B = 16. The next step is adding we have to add both squared legs together to get one number witch in our case is 25. the final step is finding your **square root** of this final added number in this case is 5. Now that we have done every step we can come to the conclusion that the hypotenuse is 5cm.

**Review,** in doing this equation is is extremely important that we follow all steps exactly. When learning the formula you have to have a basic understanding of three things, how to square, how to square root and how to tell which side is the hypotenuse. A little trick I use to find the hypotenuse is the two little lines that symbolize the ninety degree angle point to the hypotenuse.

Key words...

**Squaring-** Squaring is the number you get when you multiply the number by it by its self.

**square root- **A divisor of a quantity that when squared gives the quantity. For example, the square root of 25 is 5.