Classroom notes for 8th grade pre-algebra class.

1. Isosceles Triangle A B C

2. Isosceles Triangle with a Perpendicular Bisector A B C D

3. Isosceles Triangle with a Perpendicular Bisector A B C D

4. Isosceles Triangle with a Perpendicular Bisector Congruent side markings Perpendicular angle markings A B C D

5. Isosceles Triangle with a Perpendicular Bisector Congruent side markings Perpendicular angle markings What else do we know? A B C D

9. Isosceles Triangle with a Perpendicular Bisector If the two triangles are congruent, what else do we know? A B C D

10. Isosceles Triangle with a Perpendicular Bisector If the two triangles are congruent, what else do we know? <A = <C <BAD = <CAD All of its parts, angles and sides are congruent! A B C D

11. Isosceles Triangle with a Perpendicular Bisector A B C D You’ve used geometric reasoning to figure out more information about Δ ABC and its bisector !