3. Parts of an Isosceles Triangle The congruent sides of an isosceles triangle are the legs. The third side is the base. The two congruent sides form the vertex angle. The other two angles are the base angles. vertex angle leg leg base angles base
4. pg 161 The bisector of the vertex angle of an isosceles triangle is the perpendicular bisector of the base. If AC BC and CD bisects ACB, then CD┴AB and CD bisects AB. C A B
5. CONVERSE OF ISOSCELES TRIANGLE THEOREM pg 161 If two angles of a triangle are congruent, then the sides opposite the angles are congruent. If A B, then AC BC. C A B
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8. Find the values of x and y. xo 3. 1. yo yo 110o 60o 60o 4. 2. xo xo y 7 44o 44o 52o 10 y 4