Advice 1: How to find the area of the cylinder base

If the problem does not specify what cylinder it is (parabolic, elliptic, hyperbolic, etc.), it is assumed the easiest option. Such a spatial geometric shapes in the bases are circles and the lateral surface forms with them a right angle. Calculation of parameters in this case is not particularly difficult.
How to find the area of the cylinder base
Instruction
1
If you know the radius (r) of the base cylinder, all the other dimensions are not important in the calculations. Calculate the product of the number PI rounded to the desired degree of accuracy, the squared radius is and the area of base of cylinder (S): S=π*r2. For example, if the diameter (which, as you know, twice the radius) of the cylinder is equal to 70cm, and the result of the computation is required to obtain accurate up to the second decimal place (hundredths of a centimeter), then the footprint will be 3,14*(70/2)2 = 3,14*352 = 3,14*1225 ≈ 3848,45см2.
2
If the radius and the diameter is unknown, but the height (h) and volume (V) of the cylinder, then these parameters will also be sufficient to find the area (S) of the Foundation figures, just divide the volume by the height: S=V/h. For example, if the volume is equal to 950см3 and height in 20cm cylinder will have a base area of 950/20=47,5см2.
3
If in addition the height (h) of the cylinder is known the area of its lateral surface (p), then to find the area of the base (S) take the lateral surface area in the square and divide the result by four times the product of the number PI squared height: S=p2/(4*π*h2). For example, if the lateral surface area equal 570см2, then at the height of the cylinder is 25cm and the desired accuracy of computations in one hundredth of a centimeter, it needs to have a footprint equal to 5702/(4*3,14*252) = 324900/(12,56*625) = 324900/7850 ≈ 41,39см2.
4
If besides the area of the lateral surface of the cylinder (p) are known and the area of the whole surface (P), then subtracting the second from the first, remember to divide the result in half, as the total area includes both bases of the cylinder: S=(P-P)/2. For example, if the total area of the spatial shape is 980см2, and the area of its lateral surface - 750см2, the area of each base is equal to (980-750)/2=115см2.

Advice 2: How to find the lateral surface area of a cylinder

Calculate the lateral surface area of a cylinder it is necessary in different situations. For example, you want to sew cushion cover-cushion and you need to determine the fabric consumption. Or are you going to paint round the barrel and have to calculate the amount of paint. Maybe your goal is to Wallpaper the walls in a round room? In all these cases, you will be faced with the task to determine the area of the lateral surface of the cylinder.
How to find the lateral surface area of a cylinder
You will need
  • Calculator, roulette or the tape
Instruction
1
The lateral surface of the cylinder in the expanded view is a rectangle.

The formula for calculating the area of the cylinder surface is simple:

Bok = LхH

where Bok — the desired lateral surface area of a cylinder.

The right part of the equality represented by the product of the two multipliers:
L is the measured length of the circumference of the cylinder, H is its height.

In turn, the circumference at the base of the cylinder is calculated by the formula:

L=PI x D

where PI — the number PI is a constant and is equal to 3.1416
D — diameter circle at the base of the cylinder.

A practical method of determining the area of the cylinder surface is chosen according to circumstances.
2
Write down all your existing data on the cylinder, the lateral surface area which you need to determine.

If you know the height and diameter of the cylinder, then simply substitute in the formula for these parameters. Knowing the height and diameter of promotional stands, we can calculate the size of the poster. It is absolutely not necessary to see and measure cylindrical pedestal, on which is placed the poster.
3
Take a tape measure or measuring tape to determine the circumference of a circle at the base of the cylinder, if the cylinder is unknown.

In the absence of a flexible measuring tool you can do any rope, twine or braid. The circumference of the base of the cylinder define with a rope. The resulting segment of the rope, measure any measuring tools, such as tailor's ruler.
4
Define the height of the cylinder.

When measuring the height of the cylinder, it is important to adhere strictly to the vertical to obtain an accurate result. To define the line vertical also useful for rope, the ends of which is tied to any load. For example, conventional nuts. One end of the rope attach to the base of the cylinder. Rope under the weight of the load is strictly vertical position. Along the line vertical and should be measure the height of the cylinder.

Multiply the two received measurements of the parameter. The result of the multiplication is the lateral surface area of a cylinder.
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