## Generally used 2D Geometric Shapes

### Straight Line

A straight line is a line that never bends and has an infinite length. In general, we see straight line segments where the length of the straight line is definite(can be measured).

The following figure depicts a straight line segment.

Imagine that the above straight line segment extends infinitely at both the ends such that you cannot see the ends. Then, that could be considered as a straight line.

### Triangle

A triangle is a geometric shape with three sides.

Triangle is formed by taking three line segments and joining ends of each line segment to the ends of other line segments.

**General properties of Triangle**

- Triangle has three sides.
- Triangle has three angles.
- Sum of all the angles of a triangle is 180 degrees.

Learn more about Triangle.

### Quadrilateral

A quadrilateral is a geometric shape with four sides.

Following is picture of a quadrilateral.

**General properties of a Quadrilateral**

- Quadrilateral has four sides.
- Quadrilateral has four angles.
- Quadrilateral has two diagonals.
- Sum of all the angles of a quadrilateral is 360 degrees.

**Specific Cases of Quadrilaterals**

There are some special quadrilaterals with specific properties which are generally used in our daily life.

#### Square

**Properties of a Square**

- All the sides of a square are equal in length.
- All the angles of a square are equal to 90 degrees.
- Diagonals of a square are equal in length.

Learn more about Square.

#### Rectangle

**Properties of a Rectangle**

- Opposite sides of a rectangle are equal in length.
- All the angles of a rectangle are equal to 90 degrees.
- Diagonals of a rectangle are equal in length.

Learn more about Rectangle.

#### Rhombus

**Properties of a Rhombus**

- All sides of a rhombus are equal in length.
- Opposite angles of a rectangle are equal.
- Diagonals of a rhombus are not equal in length.

Learn more about Rhombus.

#### Parallelogram

**Properties of a Parallelogram**

- Opposite sides of a parallelogram are equal in length.
- Opposite angles of a parallelogram are equal.
- Diagonals of a rhombus are not equal in length.

Learn more about Parallelogram.

#### Trapezoid

**Properties of a Trapezoid**

- One of the two sets of opposite sides of a trapezoid are equal in length.
- Sides of unequal length in trapezoid are parallel to each other.

Learn more about Trapezoid.

### Circle

The distance from center of the circle to any point on the circumference of the circle is equal.

Learn more about Circle.