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- Two dimensional shapes can have straight lines or curved lines.

- A 2D shape has no thickness, and only two dimensions such as height and width.

- They are also known as 2D shapes.

- Many two dimensional shapes are also classified as polygons.

- A plane shape which is a closed, two-dimensional shape is a 2D shape. They vary according to the numbers of sides or vertices.

- Many 2D shapes are named according to their number of vertices. A vertex is where two sides meet. If you draw a line from two vertices that are not next to each other, this line would be called a diagonal. ( See below )

- When placed on a sheet of paper, 2D shapes lay flat.

**Ellipse** A closed loop formed by a curved line. The distance from A to C plus B to C will be constant regardless of the location of C on the curved line.

**Common Core Standard 5.G.B.3 5.G.B.4**

**Keywords**: Two dimensional figures,attributes, classify

*A triangle* has three sides and three vertices. Here is a list of some common triangles.

Polygons are classified by the number of sides. The number of sides and vertices are equal in polygons.

**Classifying polygons**** by the number of sides**

3 sides =triangle

4 sides =quadrilateral

5 sides= pentagon

6 sides =hexagon

7 sides =septagon

8 sides =octagon

9 sides =nonagon

10 sides =decagon

12 sides =dodecagon

n sides =n-gon

# 2 Dimensional Shapes

**Click on the shape for more information**

**Click on the shape for more information**

**Click on the shape for more information**

*Scalene triangles *have three different side lengths and three different angle measures

*Isosceles triangles* have at least two equal sides and two equal angle measures

*Equilateral *triangles have equal sides and angles.

A *rectangle* is a shape with four sides and four vertices

A *square *is a rectangle in which all four sides are equal length and create four ninety degree angles

A *circle* is a round shape that has no sides or corners and is not a polygon, but is a 2D shape.

A *parallelogram* has four sides, four vertices, and two parallel sides

A *quadrilateral* has four sides, four vertices, and two diagonals. There are many types of quadrilaterals. Check here for a chart of the quadrilateral family.

A *rhombus* has four sides, four vertices, and four equal sides.

A *trapezoid* has four sides, four vertices, and exactly one pair of parallel sides.

**Click on the 2 dimensional shape for more information**

**Click on the shape for more information**

## 2 Dimensional Polygon Shapes

What is a **2 dimensional shape**? A shape that has only two dimensions such as width and height, but has no thickness is considered a two dimensional shape. Polygons are 2D shapes.

**25 Names of 2D Shapes**

**Circle**: Round Shape

**Right Triangle: **3 sides 1 90 degree angle

**Rhombus:** 4 sides opposite angles equal

**Trapezoid:** 4 sides opposite are parallel

**Pentagon:** 5 sides

**Hexagon:** 6 sides

**Octagon:** 7 sides

**Nonagon:** 9 sides

**Decagon:** 10 sides

**Star:** a polygon formed by extending the sides of a pentagon

**Diamond: **also called a rhombus

**Crescent:** (looks like a sliver of the moon)

**Semi-circle: **half of acircle

**All quadrilaterals: **4 sided polygons** **

**Arrows:** also called a dart

**Convex polygon: **no internal angles 180 degrees or greater ** **

**Concave polygon: **at least one internal angle greater than 180 degrees

**Dart: **a concave dart ** **

**Kite: ** a 4 sided polygon

**Triangle: **3 sided 2d shape ** **

**Disc:** a circular shape

**Circumcircle:** the middle of the circle that touches the three vertices of a triangle** **

**Indalo:** a prehistoric magical symbol** **

**Lune:** two overlapping circles

**Oval: **think of an egg

This list is just the tip of the iceberg for two dimensional shapes.

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