Do you no longer get through the various geometric formulas to know about the circle, sphere and cylinder? What are the peculiarities of these three elements? Don’t panic, follow the guide, we demythify it all with some simple explanations of geometry.

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Article plan The

- correct geometric formula and the correct calculation The
- circle: calculation and formula
- The cylinder: calculation and formula
- The sphere: calculation and formula
- Mathematics: do not get lost between formulas

Plan de l'article

## The right geometric formula and the correct calculation

The sphere, the cylinder and the circle are elements that are related to precise geometric formulas. Each formula, which relates either to the sphere, the circle or the cylinder, has a specific function.

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Differentiate horizontal and vertical

**The snag** : it is very simple to quickly forget formulas relating to each of these elements, or to confuse them. So, in order not to forget each specific formula of calculation and finally know how to differentiate them for the sphere, the circle and the cylinder, we provide you with tips and mnemonic means.

**Between a volume, a surface, an area, a radius, a diameter, a perimeter** … The notions of geometry make us lose us there. But hang on, because it’s not necessarily the most difficult. We guide you and give you some ways to feel more comfortable with the idea of the formula, on everything related to the circle, cylinder or sphere.

## The circle: calculation and formula

When you attack the circle, we immediately think of the area of the circle and the perimeter of a circle. The perimeter of a circle is calculated using the formula **2πR** (2 x π x radius). To make the calculation of the area (surface) of a circle, the formula **πR²** (π x radion²) is used.

You only have to remember one formula to have the other one that comes in mind. The safest mnemonic means of retaining each formula inherent in the calculation of a circle perimeter or area (surface) is to pronounce the expression “2 stones”, in other words 2πR.

## The cylinder: calculation and formula

To make the calculation around a cylinder, as for the circle, there is more than one formula to remember.

Retain the calculation of the lateral area (surface) of a cylinder: **2πRh**

If you want to remember the calculation of the volume of a cylinder, here is what you need to do as a calculation: (**πR²) *h** . This means that we multiply the area (surface) of the circle by the height of the cylinder (h) to obtain the volume.

## The Sphere: calculation and formula

For a sphere, the formula for calculating the area of the sphere (its area) is as follows:

**4πR²**

For calculating the volume of a sphere, here is the formula to remember:

**( 4/3) πR³** Finally, to memorize these mathematical formulas, we provide you with some tips:

- For the volume of the sphere, the formula is pronounced four thirds pi R cube. We observe the
**rhyme between third and R**(radius), which prompts not to be confused with the calculation of the area of the sphere, or with three-quarters (3/4). - For the area (surface of the sphere, the formula is pronounced
**four ft R squared**. Imagine a sphere that includes, within itself, a circle. Then repeat the calculation and formula of the area (area) of the circle (πR²) and multiply it by 4 to find the correct area calculation of sphere.

## Mathematics: Do not get lost between formulas

Mathematics is not so complex as that and some mnemonic means make it possible to see more clearly in each formula to remember. Whether for a sphere, a cylinder or a circle, do not panic, there is always a **simple formula** to remember.

Don’t get tangled with brushes anymore and **learn these mnemonic means by heart** . This will give you the best tools to approach geometry from a betterangle.