Please note that in calculating the area and perimeter of the rectangle we use the following formula:

- Area= p x l
- Circumference = 2(p+l)

Other complete formulas can be seen in the table below

Nama | Rumus |

Area (L) | L = p x l |

Circumference (K) | K = 2 x ( p + l ) |

Length (p) | p = L ÷ l p = (K ÷ 2) – l |

Side (l) | l = L ÷ p l = (K ÷ 2) – p |

Diagonal (d) | d = √ (p^{2} + l^{2}) |

How to calculate the area and perimeter of a rectangle is very easy in comparison with other buildings. So with this formula we can easily find out the area and perimeter.

**Characteristics and Characteristics of a Rectangle**

The rectangle has the following characteristics and characteristics, this will make it easier for us to recognize a rectangle.

- Have 2 pairs of parallel and equal sides.
- One of the longer sides is called the unit of length (p).
- One of the shorter sides is called the unit width (l).
- Has 4 right angle points (with an angle of 90 °).
- Have a diagonal (d) that is the same length.

**Example 1: Calculating the Area of a Rectangle**

You know that the length of a rectangle is 20 cm and the width is 5 cm. What is the area of the rectangle.

L = pxl = 20*5 = 100 CM

**Example 2: Calculating the Perimeter of a Rectangle**

Given that the length of a rectangle is 30 CM with a width of 10 cm, what is the circumference of the rectangle

K = 2(p+l) = 2(30+10) = 2 * 40 = 80 CM

**Example 3: Find the Length if area and width are known**

A rectangle is 100 CM wide by 4 CM wide, what is the length of the rectangle?

Length= L/l = 100/4 = 25 CM

**Example 4: Find the Length if you know the perimeter and width**

A rectangle has a circumference of 80 CM by a width of 4 CM, what is the length of the rectangle?

Length= (K:2) -l = (80/2) – 4 = 40-4 = 36 cm

Area= p x l = 4 * 36 = 144 cm