GEOMETRY
Unit 4
Name _______________________
Isosceles triangles are defined as having ___________________________________________.
They have special names for their parts:
 ________: the two congruent sides
 ________: the third side
 __________ ___________: the angle opposite the base.
 __________
___________:
the angles adjacent to the base.
Isosceles Triangle Theorem:
If two sides of a triangle are congruent, then the __________ opposite those sides are
congruent.
If AB  AC, then C  B
Converse of Isosceles Triangle Theorem:
If two angles of a triangle are congruent, then the __________ opposite those angles are
congruent.
If B  C, then AC  AB
Corollary 1:
An equilateral triangle is also _______________. (and vice versa)
Corollary 2:
An equilateral triangle has three _____ angles.
Corollary 3:
The bisector of the vertex angle of an isosceles triangle is perpendicular to the
base at its _______________.
Find the value of x.
1) x = _____
2) x = _____
3) x = _____
4) x = _____
5) x = _____
6) x = _____
x + 22
3x - 5
7) Given: BC  AC; m 1 = 140, find:
m2: _____
m3: _____
m4: _____
x + 21