  # How to Calculate the Area

In childhood, we calculated areas in math class. But in adult life, we have to do it when we decorate our homes, plan where the furniture will go, and more.

5-Minute Crafts is going to show you how to calculate the areas of different geometric shapes, like rectangles, squares, circles, triangles, and trapezoids.

### How to calculate the area of a rectangle

To calculate the area of a rectangle, you need to multiply the length by the width. Let’s say you’re measuring the area of your room. The length is 6 meters, and the width is 3 meters. Multiply 6 by 3 and the area of the room comes out to 18 square meters.

### How to calculate the area of a square

The area of a square is calculated in the same way: the length is multiplied by the width. But as we already know, all the sides of a square are equal. So you just need to square the length of one of the sides.

### How to calculate the area of a circle

The area of a circle is a bit harder to calculate. You need to know the radius, which is half of the diameter. The diameter is the line that connects 2 dots on the circle and goes through its center. Measure the diameter and divide the result by 2.

✅ The formula for calculating the area of a circle is: Pi (which is about 3.14) multiplied by the radius squared.

❗The result won’t be perfectly exact because Pi is not exact.

Let’s say you’re calculating the area of a circle for a chandelier on the ceiling. Measure the diameter first. Let’s say it’s 0.46 meters. Divide it by 2 and you get 0.23 meters. Square the number: 0.23×0.23 = 0.0529. Multiply that number by Pi, which is 3.14, and you’ll get 0.1661. So the area is 0.1661 square meters.

### How to calculate the area of an equilateral triangle

Calculating the area of an equilateral triangle is a harder task.

The formula is: the square root of 3 is divided by 4 and multiplied by the length of one of the sides squared.

The square root of 3 is around 1,732. Divide the result by 4, and it should equal about 0.433. The number is the constant part of the formula. Now, one of the sides is 20 cm. Multiply 400 (20×20) by 0.433. The result is 173.2 square cm.

### How to calculate the area of a right triangle

It’s even simple to do with a right triangle: multiply 1/2 by the product of its legs (the sides next to the right angle).

For example, if the side is 6 cm and the lower side is 4 cm, this is how we calculate the area: 1/2 (6×4) = 12 square cm.

### How to calculate the area of a trapezoid

To calculate the area of a trapezoid, divide its height by 2 and multiply by the sum of the lengths of the sides. For example, if the height is 4 cm, the upper side is 3 cm and the lower side is 6 cm, h/2 (b1 + b2), the area will be calculated like this: 4/2 (3 + 6) = 2×9 = 18.