What kind of polygon is a square

An example of concave polygon is shown below. Convex Polygon If a polygon has no reflex angle , then it is said to be a convex polygon. Examples of the convex polygons are shown below.

Regular Polygon A regular polygon 's sides are all of the same length and its angles are the same size. For example, a square is a regular polygon. Known examples are for instance the left and the right side of a ladder, or the double lines you see on some freeways. Polygon: A polygon is a closed planar figure made by joining line segments. The segments may not cross, and each segment must connect to exactly two others at its endpoints. The left figure is not closed, and the figures in the middle are not made of line segments.

The figure on the right is not a polygon, since its sides intersect each other. The word "vertex" is more precise than the common term "corner", because "corner" has many other uses in English.

The plural of "vertex" is "vertices" - a triangle has three vertices. See below for more details. Also opposite sides are parallel and of equal length. A rhombus is a four-sided shape where all sides have equal length marked "s". Another interesting thing is that the diagonals dashed lines meet in the middle at a right angle. In other words they "bisect" cut in half each other at right angles. A parallelogram has opposite sides parallel and equal in length.

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. Search SkillsYouNeed:. We'll never share your email address and you can unsubscribe at any time. Properties of Polygons See also: Calculating Area. When working with polygons the main properties which are important are: The number of sides of the shape.