Honors Geometry Ch.6 Vocabulary

Flashcards for Mrs. Pawlak’s HG class.

Polygon Interior Angles Theorem

The sum of the measures of the interior angles of a convex n-gon is (n − 2) ⋅ 180°.

Polygon Exterior Angles Theorem

The sum of the measures of the exterior angles of a convex polygon, one angle at each vertex, is 360°.

Parallelogram

A quadrilateral in which both pairs of opposite sides are parallel.

Rhombus

A parallelogram with four congruent sides.

Rectangle

A parallelogram with four right angles.

Square

A parallelogram that is both a rhombus and a rectangle.

Trapezoid

A quadrilateral with exactly one pair of parallel sides.

Isosceles Trapezoid

A trapezoid with congruent legs.

Kite

A quadrilateral that has two pairs of consecutive congruent sides.

Diagonal of a Polygon

A segment that joins two nonconsecutive vertices of a polygon.

Base angles of a Trapezoid

Two consecutive angles whose common side is a base.

Midsegment of a Trapezoid

The segment that connects the midpoints of the legs of the trapezoid.

Rhombus Diagonals Theorem

A parallelogram is a rhombus if and only if its diagonals are perpendicular.

Rectangle Diagonals Theorem

A parallelogram is a rectangle if and only if its diagonals are congruent.

Trapezoid Midsegment Theorem

The midsegment of a trapezoid is parallel to each base and its length is one-half the sum of the lengths of the bases.

Kite Diagonals Theorem

If a quadrilateral is a kite, then its diagonals are perpendicular.

How can you prove that a quadrilateral is a parallelogram?

1. Show both pairs of opposite sides are parallel.

2. Show both pairs of opposite sides are congruent.

3. Show both pairs of opposite angles are congruent.

4. Show one pair of opposite sides are congruent and parallel.

5. Show the diagonals bisect each other.