Introduction To Geometry Summary Sheet (Page 3 of 4) in pdf

Ch 1 Summary

Name ____________________________

Types of Triangles:

Polygons:

polygon A closed figure in a plane, formed by connecting

Classified by angle:

line segments endpoint to endpoint with each segment

right triangle A triangle with a right angle.

intersecting exactly two others.

Isosceles Triangle Special

acute triangle A triangle with three acute

Vocab.

angles.

side (of a polygon) A line segment connecting

vertex angle (of an isosceles

consecutive vertices of a polygon.

obtuse triangle A triangle with an obtuse

triangle) The angle between the

angle.

vertex (of a polygon) An endpoint where two sides of

two congruent sides.

Classified by side:

the polygon meet.

leg The congruent sides.

scalene triangle A triangle with three sides of

angle (of a polygon) An angle having two adjacent

base (of an isosceles triangle)

different lengths.

The side opposite the vertex

sides of the polygon as its sides.

angle.

equilateral triangle A triangle whose sides

diagonal A line segment connecting two

base angles (of an isosceles

are congruent.

nonconsecutive vertices of a polygon or polyhedron.

triangle) The two angles

isosceles triangle A triangle with at least two

opposite the two congruent

congruent sides.

sides.

convex polygon A polygon with no diagonal outside the

polygon.

concave polygon A polygon with at least one diagonal

Types of Quadrilaterals:

outside the polygon.

trapezoid A quadrilateral with exactly one

pair of parallel sides.

kite A quadrilateral with exactly two distinct

congruent polygons Two or more polygons with the

pairs of congruent consecutive sides.

exact same size and shape.

Names of polygons

Sides

Name

parallelogram A quadrilateral in which both

equilateral polygon A polygon whose sides are

Triangle

pairs of opposite sides are parallel.

congruent.

Quadrilateral

rhombus An equilateral parallelogram.

equiangular polygon A polygon whose angles are

Pentagon

congruent.

Hexagon

rectangle An equiangular parallelogram.

Heptagon

regular polygon A polygon that is both equilateral and

square An equiangular rhombus; equivalently,

Octagon

equiangular.

an equilateral rectangle.

Nonagon

Decagon

Undecagon

perimeter The length of the boundary of a two-

Dodecagon

dimensional figure. For a polygon, the perimeter is the

n-gon

sum of the lengths of its sides.

Introduction To Geometry Summary Sheet Page 3

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