1. Different Types
of triangle
Classifications~~

2. An acute triangle are 3 angles that are less than 90 degrees.40 30 20
Real Life example:
Angle Measure

3. A Equiangular Triangle, has 3 congruent acute angles less than 90 degrees.60 60 60
Real Life example:
Angle Measure

4. The Right triangle is a triangle that has the angle of 90 degrees.
Real Life example:
90 degrees
90 degrees
Angle Measure

5. An Obtuse Triangle is a triangle that it’s measures are over 90 degrees.
110
Real Life example:
Angle Measure

6. We use this types of triangles to put them into categories of measurements, the triangles can be put into categories depending on the degrees that the triangles have.

7. CLASSIFY (example) Triangle ADB70 40 A B C D
Triangle ADB
Angle ADC is a right angle. Triangle ADC is a right triangle.
Triangle ABD
Angle ABD & Angle DBC form a linear pair and they are supplementary.
So m.Angle ABD + m.Angle BDC = 180.
Substitute: m.Angle ABD + 70 =180
180 – 70 = 110, so m.Angle ABD = 110.
The Triangle ABD is an Obtuse Triangle because the degree is over 90.

8. CLASSIFY (example) Obtuse Triangle Right Triangle Acute Triangle
Equiangular Triangle
130

9. An Equilateral Triangle is a triangle with 3 congruent sides.
Side Lengths
Real Life example:

10. An Isosceles Triangle has 2 congruent sides instead of all of them being congruent.
Side Lengths
Real Life example:

11. An Scalene Triangle is a triangle that has no congruent sides at all.
Side Lengths
An Scalene Triangle is a triangle that has no congruent sides at all.
Real Life example:

12. CLASSIFY (example) D E F G 20 5 17 Triangle DEF
In the figure, DE is congruent DF. So DF = 20,
And triangle DEF is Equilateral.
Triangle DEG
Using the Segment + P. we can see that
EG = EF + FG.
Substitute = 25
Triangle DEG is Scalene because none of the sides are congruent.

13. CLASSIFY (example) 2(0.9) + 6.8 = 8.6 8(0.9) + 1.4 = 8.6
2x = 8x + 1.4
-8x x
-6x = 1.4
-6x = -5.4
/ /-6
2(0.9) = 8.6
8(0.9) = 8.6
X = 0.9

14. CLASSIFY (example) 6(6) = 36 4(6) + 12 = 36 36 = 36 2y = 4y + 12
/2 /2
6(6) = 36
4(6) + 12 = 36
36 = 36
y = 6