Triangles

• A triangle is a 3-sided Polygon


• The sum of Angles in a triangle is 180°


• All triangles are convex.

An Acute Triangle is a triangle whose three angles are all Acute (less than 90 degrees).


A triangle with all sides equal
is called Equilateral.


A triangle with two sides equal is called Isosceles.


A triangle having an Obtuse Angle
(greater than 90 degrees) is called
an Obtuse Triangle.


A triangle with a Right Angle (90 degrees)
is called Right.


An Isosceles Right Triangle is also called a 45-45-90 triangle, because the measures of the angles are 45,45, and 90.


A triangle with all sides a different length is called Scalene.

how do I get the area of a triangle?

The area of a triangle equals half the product of
its base and height.
A = 1/2bh

How long is the hypotenuse of an Isosceles triangle?

Do Acute and Obtuse triangles have any special traits?

If the square of the longest side of a triangle is greater than the sum of the squares of the other two sides, then the triangle is an obtuse triangle.

If the square of the longest side of a triangle is less than the sum of the squares of the other two sides, than the triangle is an acute triangle.

What are common lengths of right triangles ?

3, 4, 5        5,12,13          8,15,17          7,24,25
6, 8,10      10,24,26
9,12,15     
12,16,20
15,20,25