Okay, let's solve this step-by-step:
1) Given: Actual area of plot = 1.28 hectares = 12800 sqm
Area shown on map = 8 sqcm
2) To calculate RF:
RF = Actual Dimension / Shown Dimension
RF = 12800 sqm / 8 sqcm
RF = 12800 / 8 = 1600
RF = 1/1600
3) Length of scale = RF x Maximum length to be measured
Maximum length = 100m
Length of scale = 1/1600 x 100m = 6.25cm = 6cm (approx.)
4) Draw a line 6cm long divided into 10 equal parts to read up to 10m
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