Triangles

Marked June 7th =__Triangles__ =

[[image:triangle_1.gif width="319" height="284"]]
===**__Types of Triangles__ There are many different types of triangles including: equilateral, isosceles, scalene, right, obtuse, and acute. **===


 * Equilateral Triangle - An equilateral triangle is a triangle with //three equal side lengths// and three equal angles of //60 degrees//. **

**Isosceles Triangle** An isosceles triangle has only //two equal side lengths// and //two equal angles//.



**Scalene Triangle** A scalene triangle has **//no equal//** sides, and **//no equal//** angles.



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A right angle triangle has one 90° internal angle.The side opposite to the right angle is the hypotenuse which it is the longest side in the right triangle. The other two sides are the //legs of the triangle. // =====

=**__Perimeter & Area__** =

To calculate **perimeter** of a triangle we use P=s+s+s. Remember to always use units, and never put a ² or a ³ because those are for area and volume P=s+s+s =7+4+7 =18cm

To calculate the **area** of a triangle we use A=bh/2 Remember to include units, the ² behind your units, ie: cm², m², km², and to divide by 2 at the end!

A=bh/2 =(4)(6)/2 =24/2 =12cm²

=__**Pythagorean Theorem**__ =

In math, we use Pythagorean theorem to find the missing side of a right angle triangle. For example: Ok, so if we wanna find the missing side length, or "c", we use c²=a²+b²

So...
c²=a²+b² c²=4²+5² c²=16+25 c²=41 /c²=/41 c=6.4 (rounded) -or- /41

There is also a couple other ways in solving a triangles missing sides rather than using the Pythagorean theorem.


 * Sines: sin //A// = //a/c,// sin //B// = //b/c.//
 * Cosines: cos //A// = //b/c,// cos //B// = //a/c.//
 * Tangents: tan //A// = //a/b,// tan //B// = //b/a.//

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=__Real World Application__ =

There is many other uses for triangles besides just math, they are used in lots of modern day structures like housing, bridges, electric pylons, and artwork can also be used in flags and signs.



**Citations:**

//Triangles// (2005). Retrieved December 10, 2008, from http://www.mathsisfun.com/triangle.html
Joyce, D. E. (1999). //Right Angles//. Retrieved December 18, 2008.

Real World Application Pictures:
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