**Geometry Chapter 2.2 Definitions and Biconditional Statements**

**I) Vocabulary**:

**A) Perpendicular**: Two lines that intersect to form right angles.

**B) Line Perpendicular to a Plane:**A line that intersects a plane in a point and is perpendicular to every line that includes that point in the plane that intersects it.

**C) Biconditional Statement**: A statement that contains the words "if and only if" (iff) and is equivalent to writing a statement combining a conditional statement and its converse. For the truth value of a biconditional statement to be true, both the conditional statemene and its converse have to have the same truth value.

**Example**: Conditional Statement: If two sides of a triangle are congruent, then the angles opposite them are congruent.

Converse Statement: If two angles of a triangle are congruent, then the sides opposite them are congruent.

Biconditional Statement: Two sides of a triangle are congruent if and only if the two angles of the triangle are congruent.