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 1

Explanation:

A=2×(L×B+B×T+T×L)

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

∴A=2×(4.2552+0.0202+0.0851)

∴A=8.721m2

V=L×B×T

∴V=4.234×1.005×0.0201

∴V=0.0855m3

Answer 2

Given:

• Length (l) = 4.234 m
• Breadth (b) = 1.005 m
• Thickness (t) = 201 cm = 0.0201 m
• Area of sheet (A) = 2(lb + bt + tl)

Area of sheet (A) = 2[(4.234*1.005) + (1.005*0.0201 ) + (0.0201*4.234)]

Area of the sheet (A) = 2*4.3604739

Area of the sheet (A) = 8.7209478 m sq.

As the thickness has at least number of significant figures 3, so rounding off area up to three significant figures, we get,

Area of the sheet (A) = 8.72 m sq.

• The volume of the sheet (V) = lbh

The volume of the sheet (V) = 4.234*1.005*0.0201

The volume of the sheet (V) = 0.0855289

Now,

Rounding off to the three significant figures, we get,

The volume of the sheet (V) = 0.0855 m sq.