Classifiying triangles by sides. Flashcards
What triangle has 3 congruent sides?
A triangle with 3 congruent sides is called an equilateral triangle
What triangle has 2 congruent sides?
Isoceles triangle.
What triangle has zero congruent sides?
Scalene triangle.
Triangle angle sum theory.
(The sum of the measures of the angles in a triangle add up to:
180.
Exterior angle sum theory. An exterior angle is formed by:
Extending any one side of the triangle
An exterior is always equal to the sum of the:
2 non-adjacent interior angles
m <1= m<2+m<3
Triangle
A closed figure with 3 straight sides.
Triangles can be classfied by their
Angles and sides.
Isoceles triangle diagram
vetex (top)
Leg (middle left) Second leg (middle right)
lower left side (base triangle) lower right side (base triangle
Right triangle diagram
Leg (Left side of right triangle) Hypotenuse right side (slanted)
Bottom leg of right triangle.
Base angles (On an isoceles triangle)
are congruent
Legs for (isoceles triangles) are
Congruent
The hypotenuse is always across from the
right angle
There are two main types of problems in geometry: The congruent statement is
side=side
Total (sum)=
side+side+side= perimeter.
Triangle Inequalities Notes part 1: = symbol is
equal to.
=x is
not equal to
<
-<
less than
less than or equal to.
> ->
greater than
greater than or equal to
Longest side —->
Opposite largest angle
The longest side is opposite the
largest angle.
Medium side —->
Oppostite (medium angle)
The medium side is opposite from the
medium angle.
Shortest side —–>
Opposite (smallest angle)
The smallest side is opposite the
smallest angle.
Triangle inequality Theorem
The sum of the lengths of any two sides of a triangle is
greater than the length of the third side.
Isoceles triangle. In an isoceles triangle, two sides are
congruent.
The two congruent sides of a triangle are called
legs.
The non-congruent side is called
the base.
The two angles at the base are called base angles
base angles
Isoceles triangle theorem (sides–>angle)
If two sides of a triangle are congruent, then
the angles opposite those sides are congruent.