How do you get the square centimeters of an area?

Answer 1

For regular shapes and a small selection of other shapes there are formulae that will enable you to work out the square area from the length of a side or sides. For some less regular shapes, you can decompose the shape into two or more regular shapes so that you can apply the formulae to get the areas of the componenets and then add them together.

For totally random shapes you have to resort to analogous measures. For example, trace the random shape onto a uniform sheet whose mass per unit area is known. Printer paper, for example, is graded by grams per square metre - you'll need mass per sq cm. Cut out the shape on the sheet and measure its mass. Divide the mass by the mass per sq cm and the answer is the area in sq cm.