Geometry

Question Analysis
This question involves identifying a biconditional statement.
The main focus is on recognizing the correct use of "if and only if."

Key Concept Explanation:
A biconditional statement requires both the original statement and its converse to be true, linked by "if and only if."

Step-by-Step Solution:
Look for the phrase "if and only if" in the options.
Option B uses "if and only if," making it a biconditional statement.
The statement is valid because both "If a triangle is equilateral, then all its sides are equal" and "If a triangle has all sides equal, then it is equilateral" are true.

Option Analysis:
A) A one-way conditional ...