Triangles

Triangles

Equilateral
Equilateral- All three sides are the same length. Isosceles- Two of the sides are the same length. Obtuse- One of the angles is greater than ninety degrees. Acute- All of the angles are less than ninety degrees. Right- One of the angles is equal to ninety degrees. Equiangular- All the angles are the same size.

All the angles in every Triangle, when added together, MUST equal 180 degrees.



Triangle Proportionality- If a line parallel to one side of a triangle intersects the other two sides then it divides the two sides proportionality.

Examples:

Example-
Find the value of X.

First you must set up the equation. X+8=12 Since 12 is the longest side you put it by itself.

Next you have to subtract 8 from 12.

X=4 is the answer.

Another answer is

4<X<20

This is called a compound inequality. it is used to help you figure out the highest and lowest value of X.

Right Triangles

Pythagorean Triples- Three positive integers that make a^2+b^2=c^2 true.Here are some Pythagorean Triples-

 * === (3, 4, 5) ===
 * === (5, 12, 13) ===
 * === (8, 15, 17) ===
 * === (7, 24, 25) ===