Math CentralQuandaries & Queries


Question from Joanne:

I found your web site through & it's great. Really hoping you can help me. We are looking at purchasing an existing home with a lot size that is advertised at 2.04 acres, however, even with my limited math skills I know this is not correct.

Their calculation takes the deepest part of the lost (179 feet) multiplied by the widest part of the lost (497.26 feet) as if it was a perfect rectangle. As you can see from the faxed diagram it is far from rectangular in shape.

Can you advise as to the true lot size? As I mentioned we are looking at this property as a purchase so time is of the essence.

I have also faxed this information (with the diagram) to the number listed on your web site. Thank you so much for your help.

Wow! Caveat Emptor!

I scanned the diagram you faxed to us, cropped it somewhat and added some lines and labels.


The best I can do is supply an estimate of the area. I am not sure I can rely on the accuracy of the diagram and the curve at the front of the property adds an additional complication. What makes this possible is that the angle at the north east corner, the angle CAB, seems to be very close to a right angle.

I joined B and C to form the triangle ABC and noted that the triangle ABC has an area very close to the area of your property. The triangle gains one of the pieces shaded yellow and loses the other, and the two yellow pieces look to have very similar areas. Since I am assuming the angle CAB is a right angle I can find the area of the triangle ABC by

triangle area = 1/2 × base × height = 1/2 × 459.41 × 179.0 = 41117.195 square feet.

There are 43560 square feet in an acre so my estimate of the area is

41117.195/43560 = 0.9439 acres.

I hope this helps,



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