Geometry Basics
Concave
a closed two dimensional shape with 3 straight sides
Triangle
has four equal sides and four equal angles
Square
a quadrilateral whose four sides can be grouped into 2 pairs of equal length sides that are adjacent to each other
Kite
a 6 sided polygon with 6 vertices and 6 angles
Hexagon
a shape is ____ if all its edges "point outward"
Convex
triangle where all three sides are equal and all three internal angles are congruent to each at 60 degrees each
Equilateral Triangle
quadrilateral with four right angles
Rectangle
a triangle that has two sides of equal length
Isosceles Triangle
a 9 sided polygon
Nonagon
exactly equal in size and shape: sides have same length, angles have same measure
Congruent
triangle in which one angle is a right angle
Right Triangle
a flat shape with opposite side parallel and equal in length
Parallelogram
a triangle with three unequal sides
Scalene Triangle
12 sided polygon
Dodecagon
a two dimensional plane shape with straight sides
Polygon
triangle where one of the internal angles is greater than 90 degrees but less than 180 degrees
Obtuse Triangle
Trapezoid
a trapezoid with two non-parallel sides the same length
Isosceles Trapezoid
7 sided polygon
Heptagon
a closed, two dimensional shape with four straight sides
Quadrilateral
triangle with three angles less than 90 degrees
Acute Triangle
parallelogram with opposite equal acute angles, opposite equal obtuse angles and four equal sides
5 sided polygon
Pentagon
10 sided polygon
Decagon