1. Bell Ringer
Find the square root, round to the nearest whole number. No calculators!

2. An Item of Business Cell phones
We had a meeting yesterday, and you are not allowed on your phones at all, even if there is “free time.”
Mr. Venna wants us to crack down on it, so do not even bring them to class.
Otherwise I will be taking them and writing you up.

3. Pythagorean Theorem
Mr. Haupt
CC A.2; CC A.3

4. Parts of a Right Triangle
A triangle has three sides, and we have two names to describe the sides.
The hypotenuse is the longest side, and it is always found directly opposite the right angle.
The legs are the two shortest sides.

5. Why does it matter?
Knowing the hypotenuse is the most important part of getting Pythagorean Theorem problems correct.
If you do not label the sides correctly, you will end up with an answer that makes no sense.

6. Pythagorean Theorem
In any right triangle, the sum of the squares of the lengths of the legs is equal to the square of the length of the hypotenuse.
The formula:
a2 + b2 = c2

8. So…?
So if you are given any two sides of a right triangle, you can find the third with a little math.
For example:

9. But why Mr. Haupt!?!?!?
Pythagorean Theorem is very useful in everyday things. Particularly in construction.
We want our doors and windows to be nice 90 degree angles right? Otherwise our house would look like something from Dr. Seuss.
We don’t want houses to look like garbage and fall apart, so the Pythagorean theorem can help.
We can use a special right triangle (3-4-5) to make sure that the corners are 90 degrees.

11. Examples

13. The best three triangles ever…