What type of polygon has 5 sides

This article will tell you everything you need to know about pentagons. A polygon is a flat, enclosed shape that is made up of straight lines. There are two basic categories of polygons: regular and irregular. Regular polygons have equal sides and equal angles. Irregular polygons do not. Pentagons can be both irregular and regular, meaning that they can have both equal sides and equal angles as well as have unequal sides and unequal angles. A pentagon is any polygon that has five sides and five angles.

As I just mentioned, in order for a shape to qualify as a pentagon, it needs to be a five sided shape and have five angles.

A regular pentagon has all equal sides and angles. In a regular pentagon, its interior angles are degrees and its exterior angles are 72 degrees.

The angles of a pentagon add up to degrees. The shape on the left is a regular pentagon. It has five sides and five angles, all of which are the same length or size.

The shape on the right is an irregular pentagon. Each side is a different length. Each angle is a different size. A pentagon is a type of 5 sided shape called a polygon. Polygons are flat, enclosed shapes with sides that are straight lines. How many sides does a pentagon have? A pentagon is a polygon that has five sides. Here are the hardest math questions on the ACT , too.

If you need a little extra practice, why not check out some math prep books? Irregular Quadrilateral : a four-sided shape where no sides are equal in length and no internal angles are the same. A six-sided shape is a hexagon, a seven-sided shape a heptagon, while an octagon has eight sides…. The names of polygons are derived from the prefixes of ancient Greek numbers. The Greek numerical prefix occurs in many names of everyday objects and concepts.

These can sometimes be useful in helping you remember how many sides a polygon has. For example:. There are names for many different types of polygons, and usually the number of sides is more important than the name of the shape. A regular polygon has equal length sides with equal angles between each side. Any other polygon is an irregular polygon , which by definition has unequal length sides and unequal angles between sides.

Circles and shapes that include curves are not polygons - a polygon, by definition, is made up of straight lines. See our pages on circles and curved shapes for more. The angles between the sides of shapes are important when defining and working with polygons. See our page on Angles for more about how to measure angles. There is a useful formula for finding out the total or sum of internal angles for any polygon, that is:.

Furthermore, if the shape is a regular polygon all angles and length of sides are equal then you can simply divide the sum of the internal angles by the number of sides to find each internal angle. As well as the number of sides and the angles between sides, the length of each side of shapes is also important. If your shape is a regular polygon such as a square in the example above then it is only necessary to measure one side as, by definition, the other sides of a regular polygon are the same length.

It is common to use tick marks to show that all sides are an equal length. In the example of the rectangle we needed to measure two sides - the two unmeasured sides are equal to the two measured sides. It is common for some dimensions not to be shown for more complex shapes. In such cases missing dimensions can be calculated. The missing horizontal length can be calculated. Take the shorter horizontal known length from the longer horizontal known length.

The simplest and most basic polygon for the purposes of calculating area is the quadrilateral. To obtain the area, you simply multiple length by vertical height. For parallelograms, note that vertical height is NOT the length of the sloping side, but the vertical distance between the two horizontal lines. This is because a parallelogram is essentially a rectangle with a triangle cut off one end and pasted onto the other:. You can see that if you remove the left-hand blue triangle, and stick it onto the other end, the rectangle becomes a parallelogram.

The area is length the top horizontal line multiplied by height, the vertical distance between the two horizontal lines. To work out the area of a triangle , you multiple length by vertical height that is, the vertical height from the bottom line to the top point , and halve it. This is essentially because a triangle is half a rectangle. To calculate the area of any regular polygon , the easiest way is to divide it into triangles, and use the formula for the area of a triangle.

See our page Calculating Area for more, including examples. See our Introduction to Trigonometry page for more information. Continue to: Calculating Area Curved Shapes.