Pythagorean Theorem By now you are able to find the area of a triangle, surface area of a triangle...
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Transcript of Pythagorean Theorem By now you are able to find the area of a triangle, surface area of a triangle...
Pythagorean TheoremBy now you are able to find the area of a triangle, surface area of a triangle and the volume of a triangular prism. All of these formulas deal with the space of a triangle, but what about the sides.
The Pythagorean Theorem allows you to find any of the given sides of a right triangle. Thinking back to our angle unit a right triangle is a triangle with a 90 degree angle.
Pythagorean Theorem Continued
• The Pythagorean Theorem comes to us from the Greeks. Credit is given to a man named Pythagoras (570 BC – 495 BC.) It is possible that he wasn’t the one who actually came up with the formula.
a + b = c
So where is it used?
• The Pythagorean Theorem is used anytime you know two sides of a triangle but not the third. Some examples are pitching a tent and needing to know how long a rope needs to be to tie it to the ground. Another example might be archery when trying to make an up hill shot. Perhaps you are building a house and need to figure out how long the trusses need to be.
a + b = c
How do you use it.a + b = c
4+ 6 = c
16+ 36 = 52
c = 52
Where does it come from
• As you can see the area of the square labeled see is the size of a and b added. This is where the formula comes from.
What is the square root of 52?• Remember that when we take a number to the second
power we have multiplied that number by itself. The inverse of taking a number to a power is to find the root of the result. Therefore what two numbers multiplied by each other result in 52.
In this case we know that it would be between 7 and 8, because 7 X 7 =49 and 8 X 8 = 64.
Challenge keep trying numbers between 7 and 8 to see if you can find an exact answer, or is the answer irrational such as the square root of 2?
Application
• Last week you began building a floor plan. This week I would like you to design your roof. Using the Pythagorean theorem please design a roof system for your house.
• What will the total cost be of the roof. Don’t worry about staying in your budget for this one.