1. GETTING TO KNOW TRIANGLES

2. Triangles are everywhere.
They can be found bracing a bridge.

3. Triangles can be found racking up billiard balls.

4. Triangles can be seen holding up shelves.

5. A triangle is a polygon with 3 sides.
Triangles can be classified by sides.
Triangles can be classified by angles.

6. TRIANGLES BY SIDES
SCALENE
ISOSCELES
EQUILATERAL

7. SCALENE TRIANGLE
WHEN 3 PEOPLE GET ON THE SCALES TO SEE HOW MUCH THEY WEIGHT, EACH ONE WEIGHS A DIFFERENT AMOUNT. SO…………

8. A scalene triangle has no equal sides.
All sides are different lengths.

9. Isosceles Triangles Isosceles triangles have 2 equal sides.
The angles opposite the equal sides are also equal. <B = <C AB = AC

10. Equilateral Triangles
All 3 sides of an equilateral triangle are equal.
Each angle of an equilateral triangle are equal.
Each angle must be 60 degrees.

11. Now let’s review.
What kind of triangle has all 3 sides and angles equal?

12. Equilateral Triangle

13. What kind of triangle has all sides a different length ?

14. SCALENE TRIANGLE

15. What kind of triangle has 2 equal sides?

16. AN ISOSCELES TRIANGLE

17. TRIANGLES BY ANGLES
Acute
Right
Obtuse

18. Acute triangles All angles are less than 90 degrees.

19. A right triangle has one 90 degree angle.

20. OBTUSE TRIANGLE
An obtuse triangle has one obtuse angle. The obtuse angle is more than 90 but less than 180 degrees.

21. DISCUSSION QUESTIONS
Is it possible to have a right equilateral triangle?
Could you have a triangle that is isosceles and acute?

22. CREDITS Microsoft clip art. wwwmath.com/school/subject/practice