Chapter 1 Vocabulary - Discovering Geometry

Equiangular Polygon

• the point on the segment that is equidistant from the endpoints of the segment
• a polygon where all the angles have the same measure
• an angle whose measure is less than 90º but greater than 0º
• part of a line that is bounded by two end points

Equilateral Polygon

• a polygon where all the sides have the same measure
• an angle whose vertex is the center of the circle and sides are radii
• a polygon where at least one diagonal is outside the polygon
• a geometry tool used to measure angles

Quadrilateral

• a polygon with four sides
• an arc that is smaller than a semicircle
• classify, differentiate, test (look for counterexample)
• (1) lines are straight.

Polygon

• A figure that is formed by the set of all points in a plane at a given distance from a given point in the plane.
• a closed figure in a plane, formed by connecting line segments endpoint to endpoint with each segment intersecting exactly two others.
• angles that have the same measure
• a polygon with four sides

Hexagon

• angles that have the same measure
• a six-sided polygon
• (2) two lines are perpendicular just because they look perpendicular - they must be marked with a 90º symbol
• on the same line

Trapezoid

• a polygon with eight sides
• a quadrilateral with exactly one pair of parallel sides
• on the same line
• You represent a line by giving the letter names of any two points on the line and by placing a line symbol above the letters.

Parallelogram

• a line extending in one direction from a point
• a quadrilateral whose opposite sides are parallel
• a polygon with eleven sides
• (3) points on a line are collinear and all points shown on a diagram are coplanar.

Rectangle

• a parallelogram that is equiangular
• a polygon with twelve sides
• two angles that share a vertex, a common side, and their non-common sides form a line.
• a polygon that is both equilateral and equiangular

Rhombus

• a parallelogram that is regular
• unit for measuring angles
• a parallelogram with four congruent sides. In other words, a parallelogram that is equilateral
• (3) points on a line are collinear and all points shown on a diagram are coplanar.

Acute Angle

• A surface with no thickness that extends infinitely along its length and width.
• A polygon where no diagonal is outside the polygon
• a line segment that connects two nonconsecutive vertices of a polygon
• an angle whose measure is less than 90º but greater than 0º