Transcript 4.3 Isosceles and Equilateral Triangles

4.3 ISOSCELES
AND
EQUILATERAL
TRIANGLES
VOCABULARY
Two angles of an isosceles triangle are
always congruent. These are the angles
opposite the congruent sides
BASE ANGLES
THEOREM
If two sides of a triangle are congruent
, then the angles opposite them are
congruent
EXAMPLE 1
Use the Base Angles Theorem to find
the measure of <L
CONVERSE OF BASE
ANGLES THEOREM
If two angles of a triangle are
congruent, then the sides opposite
them are congruent.
EXAMPLE 2
Use the converse of the base angles
theorem to find the value of x
YOU TRY IT…
EQUILATERAL
THEOREM
If a triangle is equilateral, then it is equiangular.
EQUIANGULAR
THEOREM
If a triangle is equiangular, then it is equilateral.
EXAMPLE 3
YOU TRY IT…