Units and Measurement

Question

The length, breadth and thickness of a rectangular sheet of metal are 4.234 m, 1.005 m, and 2.01 cm respectively. Give the area and volume of the sheet to correct significant figures.

Answer

Given, 
Length, l = 4.234 m 
Breadth,b = 1.005 m 
Thickness, t = 2.01 cm = 2.01 × 10-2 m

Area of the sheet = 2 (l × 0 + b × t + t × l)

                       = 2 (4.234 × 1.005 + 1.005 × 0.0201 + 0.0201 × 4.234)

                       = 2 (4.3604739)

                       = 8.7209478 m2

Area can contain a maximum of three significant digits, therefore, rounding off, we get

Area = 8.72 m2

Also, volume = l × b × t

               V = 4.234 × 1.005 × 0.0201

                  = 0.0855289
                  = 0.0855 m3 (Significant Figures = 3)

 

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