Posted: 11/15/2004 1:56:46 PM EDT
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I need to figure square footage of an irregular area. I know if it was circular, I could get the area using pi Rsquared. Does this also work if you know circumference/perimeter of the irregular area? I could figure the equivalent radius by dividing the perimeter measurement by pi and dividing by 2. This should give me the equivalent circular area if I use the pi rsquared formula. In other words, how do I figure area knowing outside measurements only? Is this possible? Thanks. |
 you just hurt my brain. 
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One method would be to make sure it is to some scale and put a grid over it. Then count up how many unit grid squares the area covers, estimating the portions of those that are only partially covered. Add all of them up and there you have it. The key is making sure the grid and drawing match in scale, i.e. 1 foot on a particular side of the area equals one grid square side length. Got it? |
You can estimate the area by dividing it into square blocks of known measurements. If you need an exact measurement, then you need calculus. What kind of irregular area is this exactly? |
Very clever idea. Awfully sensitive to minor "errors" but an interesting approach. |
yeah didn't they teach that 5 step method in calc II. like find a generic area of the ith peice and blah blah blah. basically if you can make 2dimensional equations for each of the segments it can be done exactly. edited to add: don't ask for help, that was a few maths ago. sorry. |
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you can only use Pi*RR if you have a circle. you can find what the radius of a circle with equivalent area would be, but thats only after you find the area of the irregular shaped object. get a picture of your problem up here and I'll solve it and show you how. The only time you would need calculus is if your borders were defined as functions. I could do that too if thats the case. Edit: since its a driveway always get more that you need. just do a rough estimate on graph paper done to scale. Count up your squares and take into accound your scale ratio and your done. |
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Get more than you need, what you have left over can be used for a walk way or better yet the firing line on you new range! Everyone hear that, texashark is installing a range at his house! I'm packing the truck and getting ready to head on down. Back to reality (the buzz is wearing off); if you have straight lines you can use the area formula for a rectangle then play around with the area of a circle for the curves. If you can get a rough picture up with measurements you could turn this into a contest. First one with the correct numbers up gets gets to be named the ar15.com math god or something like that. Get the numbers up and let us play! edit form some spelling misstakes 
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