How to figure square foot of pathway

[ArmadilloLawnCare]

Can you tell me how to figure the square footage of an arc shaped pathway. Here are the dimensions:
Outer portion of the arc is 24'
Inner portion of the arc is 14'
Width of the path is 4'
The way I figured it I came up with 75 sq feet and I want to know if that is right. Thanks for the help.

[CCLS]

Draw us a picture.

[Scott]

measure down the middle then mult. x4

[MASTERMOWER]

Measurement calculations for irregular areas.

Sorry in advance for my crummy scanning job. I quickly drew these up, scaned them, and then had to reduce the photo size and in the process things went a little fuzzy. Anyhow, the first draw up is for your question. Scott was right on, take the middle of the sidewalk measurement (or average of the two outside measurements.) The second draw up I threw in (your lucky day!!) It is for some very irregular area, such as a bed, where you want to get an accurate area measurement for. Often people do not know how to measure such an area accurately.

I hope all is understandable.



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[bellarine lawns]

Here is a link to a calculator that will provide you with calculators for just about everything.

http://www.csgnetwork.com/cuberootcubecalc.html

You need to use a general area calculator, select a trapezoid calculator which basically is half the sum of the two longest paralell sides X the width ie 14+24=38/2=19x4=76sq.ft.
Mastermowers arc calcs. which gave an answer of 87.5sq are obviously wrong. the correct answer is always going to be somewhere halfway between 24x4=96 and 14x4=56 the difference between those two calcs. is 40. the half of 40 is 20. so if you add or subtract 20 from 56 or 96 you get 76, which is the same answer as using the trapezoid calculator.

[MASTERMOWER]

Mastermowers arc calcs. which gave an answer of 87.5sq are obviously wrong. the correct answer is always going to be somewhere halfway between 24x4=96 and 14x4=56 the difference between those two calcs. is 40. the half of 40 is 20. so if you add or subtract 20 from 56 or 96 you get 76, which is the same answer as using the trapezoid calculator.

Please re-read through my instructions carefully. You will see I too got 76 SF. I then added 15% on top of that to account for extra material needed for the project. So say if this where a brick sidewalk job and you rolled up to the jobsite with only 76 SF worth of bricks you will be short.....guaranteed! You have to account for the bricks you'll be cutting or even the defective ones. This is why you should add 15% extra for materials.

So again, 76 SF x 1.15 = 87.4 SF.

One last note: If you have to rely on a website to provide you with calculations you are at a disadvantage. Being able to perform this simple algebra in your head will give you an advantage (even if it may be a small one) in this business.

[bellarine lawns]

Oops, please accept my apology. I originally did the calcs in my head when I read Armadillolawncares posting and came up with 76.
This calculator site is awesome...I came across it when I was helping a friend do calculations for a landscaping course he was doing. He couldn't even calculate the area of a square, so you can imagine the problems he was having when confronted with circles, arcs and volume areas. At times I felt like I should be doing the course as I have done/helped him with most of the course. I shake my head sometimes at the quality of the teaching and the poor unrealistic assignments that he has to do..the last one he has just completed is sowing a seed lawn on a rock hard soil area. the site preparation, soil test andconditioning, etc was pretty much non extistent but that is how the lecturer taught the class .

[Stephen M.]

Scott, you can't go wrong w/ the Seahawks this year. Man, what a turn around from last year!!!

[ArmadilloLawnCare]

MASTERMOWER
Thanks for the help. I still haven't figured out how to post pictures so I wasn't able to post a picture of the path but you nailed it with your drawing. I appreciate the assistance.