Geometry Vocabulary Words: Chapters 1-7

Inverse

"If not p, then not q"

Contrapositive

"If not q, then not p", always has the same truth value as conditional

Trapezoid

A quadrilateral with exactly one pair of parallel sides

Kite

A quadrilateral with two pairs of congruent consecutive sides and no opposite sides congruent

Parallelogram

A quadrilateral with two pairs of parallel sides

Altitude of a Triangle

The height of the triangle; a segment that goes from a vertex and form a right angle with the opposite side

Converse

The statement obtained by reversing the hypothesis and conclusion of conditional; "if q, then p"

Adjacent angles

Two coplanar angles that have a common side and a common vertex but no common interior points

Similar figures

Two figures that have the same shape but not necessarily the same size

Parallel lines

Two lines that lay in the same plan and do not intersect

Angle

Two rays with the same endpoint; the rays are the sides of the angle and the common endpoint is the vertex of the angle

Coordinate proof

Using coordinate geometry and algebra to prove theorems

Rhombus

A parallelogram with four congruent sides

Rectangle

A parallelogram with four right angles

Square

A parallelogram with four right angles and four congruent sides

Equidistant

A point is _______ from two objects if it is the same distance from the objects

Regular polygons

A polygon that is both equilateral and equiangular, its center is the point that is equidistant from it verticies

Segment Bisector

A line, segment, or ray that intersects a segment at its midpoint

Perpendicular Bisector

A line, segment, or ray that is perpendicular to the segment at its midpoint

Linear pair

A pair of adjacent angles whose non common sides are opposite rays

Theorem

A conjecture that must be proven

Transversal

A line that intersects two more coplanar lines at a distinct point

Angle Bisector

A ray that divides an angle into two congruent angles

Perpendicular bisector of a Triangle

A segment that is perpendicular to a side of a triangle and cuts the side in half

Midsegment of a Triangle

A segment that joins the midpoints of two sides of the triangle

Median of a Triangle

A segment that starts at the vertex of a triangle and goes to the midpoint of the opposite side

Isosceles Trapezoid

A trapezoid whose nonparallel sides are congruent

Postulate

An accepted statement or fact

Conditional

An if-then statement

Opposite rays

Collinear rays with the same endpoint; they form a line

Angle bisector of a Triangle

Cuts the angle of a triangle in half

Construction

Geometric figure made with only a straightedge and compass

Skew lines

Lines that do not lie in the same plane and never intersect

Concurrent

Meeting at the same point

Parallel planes

Planes that do not intersect

What are the three undefined terms ?

Points Lines Planes

Congruent polygons

Polygons that have corresponding sides congruent and corresponding angles congruent

Hypothesis

The part of an if-then statement that follows if

Conclusion

The part of an if-then statement that follows then

Point of concurrency

The point at which multiple lines intersect

Orthocenter

The point of concurrency of the altitudes of a triangle

Incenter

The point of concurrency of the angle bisectors of a triangle

Centroid

The point of concurrency of the medians of a triangle

Circumcenter

The point of concurrency of the perpendicular bisectors of a triangle

Midpoint

The point that divides the segment into two congruent segments

Scale factor

The ratio of corresponding linear measurements of two similar figures

Midsegment of a Trapezoid

The segment that joins the midpoints of the nonparallel opposite sides of a trapezoid

Supplementary angles

Two angles whose measures add up to 180 degrees

Complementary angles

Two angles whose measures add up to 90 degrees

Vertical angles

Two angles whose sides form two pairs of opposite rays