how to calculate area of circles etc

[tfs]

As Im not working today I though I would make a quick how to for any newbies or anyone who may not know what formula to use for calcuting tile quanties for design works which include tiling circular areas. I know to some, this may seem basic but, I have heard this type of question many times so hopefully some of you will find this to be usefull.

Radius = centre to outside of circle
Diameter = distance from one side to the opposite side of circle
Circumference = distance around the circle



Whenever calculating area for circular spaces on the floor, wall or even pillars we must do so using the radius, Diameter and circumference. With these measurements we can calculate areas by adding Pi (3.14159) into the formula.

For example to calculate the are of a circle to get your tile requirements you first of need to measure the radius (as shown in the pics) you then multiply the radius by radius, you then multiply this sum by pi(3.14159) and this will give you the area of the circle. Here is an example/ demo;

Let say the radius of the circle is 0.8mtr

Radius = 0.8mtr

r2 = (radius x radius) = 0.64mtr

r2 X PI (0.64mtr x 3.14159) = 2.01mtr

Total area of circle = 2.01square mtr

Formula = r2 x Pi = area


If you are in a position where you need to calculate the area of a pillar then you use a simpler formula. The formula for working out the area of a cylinder is;

circumference x height of pillar

However due to both top and bottom of pillar not being accessible to measure we will not use the diameter to calculate the circumference like we did with the circle. It is actually easier to physically measure the circumference of a pillar unlike that of a circle. One way to measure the circumference of the pillar would be to use a flexible tape (such as those used by tailors etc) with this you can then measure the distance round the pillar (circumference) and then multiply this figure by the height.

For example;

Lets say the height of the pillar is 300cm, you measure the circumference of the pillar with your tape and it equals 40cm.

Circumference .4m x Height 3.m = 1.2square mtr

Total area of pillar = 1.2 sqm

[Dave]

Isn't that pic an Oval..




Joking aside mate, cracking post.

[tfs]

Isn't that pic an Oval..




Joking aside mate, cracking post.

Probably is slightly oval,

made it up on word document you get little shapes that you need to size yourself.

[kilty55]

another great post kris

[aph257]

nice one.

[user123]

Brilliant Used to love geometry, didn't expect to see it on here somehow!