Why area uses square units — and conversions must be squared
Understand why changing centimetres to metres changes area by 10,000 rather than 100, with exact metric and imperial examples.
Read guideUnderstand the measurement
Area guides with the measurement boundary visible
Three guides explain squared unit factors, perpendicular height, and the difference between exact π and a decimal approximation.
Perpendicular height in triangle, trapezoid, and parallelogram area
Learn why a slanted side is not automatically the height and how to choose the matching base-height pair.
Read guideExact area with π versus a decimal approximation
See why 9π is an exact circle area while 28.2743338823 is a useful but rounded decimal representation.
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