**Triangle**: In order to estimate the surface area of a triangle, you have to multiply the height with the base and divide this total by 2.

**Square**: Square the length of one of the sides.

**Rectangle**: Multiply the height by the length.

**Cylinder**: When you know the circumference (*the linear distance around the outside of a closed curve or circular object*), multiply the height by the circumference. When you know the diameter (*a straight line connecting the centre of a geometric figure, esp a circle or sphere, with two points on the perimeter or surface*) multiply the diameter by 3,14 and you get the circumference. Sweet! Now multiply the circumference by the height.

**Circle**: Square the radius (The radius is a line segment that joins the center of a circle with any point on its circumference. If you don’t know the radius, you can find it out by diving the diameter of the circle by 2) and multiply it by 3.14.

**Cone**: First, you need to calculate surface of the base. You can do this by squaring the **radius** and multiplying it by 3.14 (The radius is a line segment that joins the center of a circle with any point on its circumference. If you don’t know the radius, you can find it out by diving the diameter of the circle by 2). Write down this result. Next, you need to calculate the rest of the “vertical” surface. Measure the slanting side of the cone – this is your **generatrix**. Now multiply the generatrix by 3.14 and by the radius you used before. Write down this result too. Now add the two results and you found out the entire surface of your cone.

If you’d like a more simple formula, please refer to the information below:

**r** = radius

**g** = generatrix

**π **= approx. 3.14

Total surface of the cone: π r (r + g)

**Sphere**: Square the radius and multiply it by 4π. (4×3.14)

**Chain fences**: Imagine the surface area as solid and refer to the surface areas calculation methods above. Bear in mind that you should double the paint quantity if you wish to spray paint this surface. Our recommendation is to apply the paint with an extra long roller.

Now that you know what surface you’re dealing with, you can also check out the paint calculator in order to see how much of it you’ll be needing.