Area of rectangle formula with an example problem
Area of rectangle formula: Rectangles are two-dimensional shapes that we find quite often in everyday life. Starting from room ceilings, doors, tiles or floor tiles to A4 paper that we can use to print documents.
It is similar to a square with four sides, but has two different sizes. The widths and lengths of the rectangles differ from each other, but they stay parallel to form a neat construction that is easy to organize. What are the formulas associated with this wake? Here are the formulas for the area and perimeter of a rectangle along with examples.
Rectangle properties
Before going to a collection of formulas and sample questions, it helps us to know some of the properties and characteristics of rectangles. It’s simple, really.
- Have two axes of symmetry
- Occupy the frame in four ways
- Has four right angles
- Has two diagonal lines that are the same size and divide the field into two equal parts.
- Have opposite sides that are parallel and of the same length
Area of a rectangle formula
In short, the area of a rectangle is calculated by multiplying its width and length. Here’s the formula.
L= p x l
An example of the area of a rectangle is as follows.
It is known that a swimming pool has a length of 14 meters and a width of 5 meters. How wide is it?
L = 14 x 5
= 70 m²
The unit of area of a rectangle is the square meter with a square symbol above it indicating that it is a unit of area. Not only meters, it can also be converted into decimeters, centimeters, millimeters, and so on.
Perimeter of rectangle
Brothers may also need a circumference formula that can actually be calculated easily. The perimeter is basically the sum of the sides of a two-dimensional figure. So, for a rectangle all you have to do is add up the four sides. Incidentally, the sizes of the four sides are the same size, so it can be shortened to the following formula.
K = p + l + p + l
= 2p + 2l
or it can be shortened again to K = 2 x (p + l)
Here’s an example of the question:
It is known that an A5 paper has a length of 14.8 cm and a width of 10.5 cm. Count the circumference!
K = 2 x (14,8 + 10,5)
= 2 x 25,3
= 50,6 cm
For the circumference, the units do not use cubes or the power of two because they are only the sum of the four sides.
More examples of questions
If what is known to be reversed, you can still calculate it easily, really. Please consider the following example questions.
The area of the rectangle is 18 m2. The width is known to be half of the length. What is the exact length and width of the rectangle?
If l = ½ p, then 2l = p
We return to the area formula, then we find the following equation.
L = p x l
18=2lxl
18 = 2l²
l² = 9
l = 3
Thus l = 3 and p = 6
On the other hand, if what is known is the circumference, you can also calculate it quite easily. Consider the following example.
It is known that the perimeter of a soccer field in the village is 64 m. Meanwhile, it is known that the length is 3 times the width. What is the length and width of the field?
p = 3l
K = 2 (p + l)
64 = 2 (3l +l)
32 = 4l
l = 8
If l = 8, then p = 24. Easy, right?
Counting the diagonal lines of a rectangle
To calculate the diagonal line, you can use the Pythagorean formula which reads.
a² + b² = c²
In the case of a rectangle, a can be thought of as l, b as p, and c as a diagonal line
c² = p² + l²
c² = √ (p² + l²)
An example of the question is like this. If the width of the rectangle is 3 cm and the length is 4 cm, what is the length of the diagonal line?
c = √ (9+16)
c = √25
c = 5
Applications in real life
Rectangles are found in many objects, what are they?
- Starting from the laptop or TV screen. Usually the size of 14 or 21 inches is calculated from the length of the diagonal line. The same goes for cellphone screens and various other devices that use LCD screens.
- Making a table also uses the principle of a rectangle to determine its size and dimensions. Should use a beam because it also involves the thickness of the wood or cross-sectional material, but because it is thin and does not have much impact, people will focus on the length and width first. In addition to tables, many other pieces of furniture use the rectangular principle, such as mattresses and carpets. Other furniture such as cabinets and sofas are more suitable to be calculated using the beam principle because it involves thickness.
- Calculating the volume and perimeter of a cuboid is also actually an extension of the width and length of the rectangle. Later it can be used to determine the packaging of food products using cardboard and so on.
- Making building construction blueprints also uses a lot of rectangular principles. Mainly to make a draftof the land area and determine the presence of walls, doors, windows, to the required number of tiles.
You have studied a collection of area of rectangle formula and examples of questions. Hopefully it will be a valuable lesson for assignments or other needs in everyday life.
