1. Triangles
11.2

2. Classification by sides
Equilateral has all sides congruent
Isosceles has 2 congruent sides
Scalene has no congruent sides

3. Classification by Angles
Acute has 3 angles less than 90°
Right triangle has 1 angle = 90 °
Obtuse has 1 angle greater than 90 °
Equiangular: has 3 congruent angles (is also acute)

4. Right, Scalene Triangle

5. Right, Isosceles Triangle

10. Triangle Sum Theorem The sum of the measures of the interior angles of a triangle is 180°.B
mA + mB +mC = 180° A C

11. Find m<E in triangle DEF if m<D= 62 degrees and m<F= 39 degrees.

12. The measures of the angles of the triangle XYZ are in the ratio 2:3:5
The measures of the angles of the triangle XYZ are in the ratio 2:3:5. What are the measurements of the angles?

13. Exterior s (4, 5, and 6) Interior Angles (1, 2, and 3)

14. Exterior Angle Theorem
m<D +m<A =180 B C D A

15. Find x 95 x
142

16. Find X x
108
X+2

17. Homework
Page (2-26) evens