1. Add up all the sides Perimeter of Area of a Rectangle: ANY polygon:
Area of a Triangle:
Add up all the sides

2. At least two sides are congruent All sides are different lengths
Triangles
Triangles can be classified according to its ___________ or _____________
Classify by Sides:
NOTE!
Sides
Angles
Use tick marks to show congruent sides
EQUILATERAL
ISOSCELES
SCALENE
All three sides are congruent
At least two sides are congruent
All sides are different lengths

3. All three angles are acute One angle is obtuse
Classify by Angles:
The sum of the angle measures in a triangle:
ACUTE
TRIANGLE
OBTUSE TRIANGLE
RIGHT
TRIANGLE
EQUIANGULAR
TRIANGLE
All three angles are acute
One angle is obtuse
One angle is a right angle
All three angles have the same measure