View Full Version : finding area of irregular mulch beds?

lasher66

05-09-2006, 10:41 PM

Ok, I messed up. I measured a landscape area to be mulched and I measured the circumference around the irregular shaped mulch beds and thats it. Is there a way to find square ft from the circumference of an irregular area alone? For some stupid reason, I was thinking that if you took a rope and made a circle, you could bend it to different shapes and the area would still be the same inside it. From my calculations so far, I dont think this is true. I know I should have just divided it into rectangles and came up with a close figure. The circumference of the area is 364 ft. Any help would be greatly appreciated. Thanks

Jason

procut

05-12-2006, 12:11 AM

Using the circumference of 364' that you gave, I made a few quick calculations, and get a little over 10,000 sq. ft. Not 100% sure if it is correct though. hope it helps!

procut

05-12-2006, 12:13 AM

I just realized something else, it would have to be a perfect circle for that figure to be correct.

lasher66

05-12-2006, 09:36 AM

Yeah, I already went back and remeasured the beds. I found that there is no way to decide the area just by the circumference. Just another dump mistake I made. Thanks anyways.

Jason

Critical Care

05-12-2006, 12:47 PM

Don't think you can do it on circumference alone, but there are different ways to figure irregular shaped areas. For an area that is roughly circular in shape, pick out a spot that is close to the center of the area. Measure the distance from the center to the outside in every 10 degree increments, or so. From this information you can get a good average on the radius. Now you just solve for the area of a circle, which can be figured .785 x d x d.

For a shape like the one below, measure across the longest length (red) and then take the average of a number of cross distance measurements (green). Then just figure as a rectangle.

kemmer

05-13-2006, 08:22 PM

Or just do this

10,201 using the circumference you gave.

If you take a string and outline the bed, you can get the circumference (364'). Once you have the circumference, use c/d = pi to get the diameter (115'). Once you have the diameter, take 1/2 that to get the radius (57'). Then use a= pi * r squared to get the area. (10201)

scott's turf

05-15-2006, 02:13 PM

I think you mean perimeter not circumference. A circumference is only for a circle not the irregular shape you describe. Unfourtunally a perimeter will not give you an area unless you know the type of shape it is.

Let me ask, if you have a string, lets say 40' long, would it matter if it was made into the shape of a square (5'sides) or a circle...wouldnt the area inside remian the same and just the outside shape change??? ie, as long as the sting stays the constant length, any shape you make out of it should come up with the same area, right???

Maybe Im confusing myself, but if you take the shape above, measured the outline with a string, then made that into a circle, coundnt you find the area that way???

lasher66

05-16-2006, 12:52 AM

Let me ask, if you have a string, lets say 40' long, would it matter if it was made into the shape of a square (5'sides) or a circle...wouldnt the area inside remian the same and just the outside shape change??? ie, as long as the sting stays the constant length, any shape you make out of it should come up with the same area, right???

Maybe Im confusing myself, but if you take the shape above, measured the outline with a string, then made that into a circle, coundnt you find the area that way???

That is exactly what I was thinking, BUT if you take the string and make an oval, almost to the point to where the two side of the string are touching, there is almost no area with the same perimeter. So that is how I proved myself wrong. Plus I took different shapes like squares and rectangles and gave them different length side,but made is so all the sides added up to the perimeter I came up with, the results showed different areas in each when using Length times width. So you have to use the methods for perfect circles or other shapes to find area.

Jason

Critical Care

05-17-2006, 02:40 AM

Snowyleaflandscaping, that's the idea. Most people can visualize roughly what the average length and width, or radius, would be of an area once it is drawn on paper, but trying to estimate these averages on site without any measurements can really be guesswork,

Here is one example I tried. If a square has a perimeter of 100’ consisting of four 25’ sides, its area would be 625 square feet. If we keep that same 100’ perimeter but make it into a circle then the area becomes about 797 square feet. Considering different shapes with the same perimeter, a circle will have more area.

Snowyleaflandscaping, that's the idea. Most people can visualize roughly what the average length and width, or radius, would be of an area once it is drawn on paper, but trying to estimate these averages on site without any measurements can really be guesswork,

Here is one example I tried. If a square has a perimeter of 100’ consisting of four 25’ sides, its area would be 625 square feet. If we keep that same 100’ perimeter but make it into a circle then the area becomes about 797 square feet. Considering different shapes with the same perimeter, a circle will have more area.

Yeah that makes sense. I still dont understand if you have a certain shape (think of the set string outline), and just change around the configuration, you arent really increasing or decreasing the area inside the shape (string), but I guess you are.;) ;) :confused:

Critical Care

05-18-2006, 09:38 PM

Yeah that makes sense. I still dont understand if you have a certain shape (think of the set string outline), and just change around the configuration, you arent really increasing or decreasing the area inside the shape (string), but I guess you are.

Seems strange for sure, and you know, it really isn't hard to figure, but just hard to visualize why.

An easier one to compare to that square with the 100' perimeter would be a rectangle with the same 100' perimeter. If the square has four 25' sides, the area again would be 625 s.f., and if the rectangle has two 40' sides and two 10' sides, that area suddenly drops down to 400 square feet (40 x 10).

So, if a circle with a specific perimeter naturally has more area within it, then why are we so square oriented? I think we should all go out and make some round landscape trailers.

Oldtimer

05-22-2006, 12:50 AM

Try this web site.

http://www.upstatemulch.com/calculator.htm

Oldtimer

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