1. Classify Triangles
Standard 4C

2. What is a Triangle?
A triangle is a polygon with 3 sides. A triangle can be formed from three line segments if and only if the sum of the lengths of any pair is greater than the length of the third segment.

3. Acute Triangles
Acute triangles are triangles in which all 3 interior angles are less than 90°

4. Obtuse Triangles
Obtuse triangles are triangles in which 1 interior angle measure is greater than 90°

5. Right triangles have 1 angle that is 90°

6. Equilateral Triangles
Equilateral triangles have three sides of equal length and each angle measures 60°

7. Isosceles Triangles
Isosceles triangles have at least 2 equal sides (an equilateral triangle is a special case of an isosceles triangle)

8. A scalene triangle is a triangle with NO congruent sides
Scalene Triangles
A scalene triangle is a triangle with NO congruent sides