Is DE DF ? Explain
D
58
161
A.
Yes; ZF = 61, so DE is congruent to DF by the Isosceles Triangle Theorem.
B.
Yes; mZF =61, so DE is congruent to DF by the Converse of the isosceles Triangle Theorem.
O
C. No; the measure of ZF is not given, so it is not known whether A DEF is isosceles or not. Thus no pair of sides in A DEF can be
proven congruent.
O D. No; although A DEF is isosceles, it is not known whether ZF is congruent to ZE or LD, so it is not known which pair of sides in
ADEF are congruent.