1. Lesson 6-4 Isosceles Triangles

2. Ohio Content Standards:

3. Formally define geometric figures.

4. Ohio Content Standards: Formally define and explain key aspects of geometric figures, including: a. interior and exterior angles of polygons; b. segments related to triangles (median, altitude, midsegment); c. points of concurrency related to triangles (centroid, incenter, orthocenter, and circumcenter); d. circles (radius, diameter, chord, circumference, major arc, minor arc, sector, segment, inscribed angle).

5. Isosceles Triangle:

6. A triangle that has a least two congruent sides.

7. Isosceles Triangle: legs The congruent sides are called legs.

8. Isosceles Triangle: base The side opposite the vertex angle is called the base.

9. Isosceles Triangle: Vertex Angle Leg Base Angles

10. Theorem 6-2 Isosceles Triangle Theorem

11. If two sides of a triangle are congruent, then the angles opposite those sides are congruent.

12. Find the values of the variables. x°x° y°y° 35° 45°

13. Theorem 6-4 Converse of Isosceles Triangle Theorem

14. If two angles of a triangle are congruent, then the sides opposite those angles are congruent.

15. D 1 2 E F 3x - 3 2x + 2

16. Assignment: Pgs. 249 – 250 6-14 all 19-21 all