Answer: Approximately 96 square feet
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Work Shown:
1 ft = 30 cm
1 ft = (5*6) cm
1 ft = 5*(6 cm)
1 ft = 5*(1 board width)
1 ft = 5 board widths
12*(1 ft) = 12*(5 board widths)
12 ft = 60 board widths
12 ft = 1 full wall length
The wall is 12 feet horizontally across and 8 feet tall, so its estimated area is 12*8 = 96 square feet approximately. This is approximate because of the fact we used the approximation of 1 ft = 30 cm.