# Polygons

**Rectangles**

The perimeter of a rectangle where length is written as *l* and width written as *w *is as follows*:*

Perimeter = 2*l* + 2*w* or 2(*l* + *w*)

The area of a rectangle is written as:

Area = *lw*

**Squares**

The perimeter of a square where *l *represent length is:

Perimeter = 4*l*

The area of a square is given as:

Area = *l*²

**The area of a triangle**

The area of a triangle, where the base is represented as *b* and height is represented as *h* is as follows:

Area of triangle = ½*bh*

Point to note: Any side of the triangle can be taken as the base so long as the height is perpendicular to it.

If only the length of the sides and angle are provided, trigonometry can be used to find the area of a triangle:

Area of triangle = ½ *ab *sin C

*a* & *b* – represents the length of two sides

C – represents the angle between *a* and *b*

**The area of a parallelogram**

The area of a **parallelogram** can be found using the formula, where *b* represents base length and *h* represents the height:

Area of parallelogram = *bh*

**The area of a trapezium**

The area of any **trapezium** can be found using the formula, where *a *represents one side and *b* represents the opposite side and *h* represents the height.

Area of a trapezium = ½(*a* +*b*)*h*