40.96 mm
3.2(10) = 32; 3.2 cm → 32 mm
each side of scale drawing is 32 mm
2(10) = 20; 2 cm → 20 mm
scale is 4 mm to 20 mm
[tex]\frac{4}{20}= \frac{x}{32}[/tex]
cross-multiply:
32(4) = 128
128 / 20 = 6.4
each side of the actual drawing is 6.4 mm.
6.4 * 6.4 = 40.96
40.96 mm
