SOLUTION: Kidney outer and inner shape. If I know the distance in feet around the outer irregular shape and the distance around the inner irregular shape how do I compute the square footage

Question 1160594: Kidney outer and inner shape. If I know the distance in feet around the outer irregular shape and the distance around the inner irregular shape how do I compute the square footage of the area between the 2 shapes?
Found 2 solutions by ikleyn, Alan3354:
Answer by ikleyn(52790) (Show Source): You can put this solution on YOUR website!
.

In general case --- there is NO way.

To get some estimations, it requires to make some assumptions.

For example, if both shapes are polygons (convex polygons), then there are analytical formulas for their areas
via the coordinates of their vertices.

Knowing the areas for each, you may find the area in between by subtraction.

In other case, if the outer shape is a narrow strip of uniform thickness around the inner shape,
then the area of this strip is its width multiplied by the half the sum of the perimeters of the shapes.

Answer by Alan3354(69443) (Show Source): You can put this solution on YOUR website!
google "planimeter"
Maybe "plainimeter"
========
A thing that rolls around the perimeter and gives the area.

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