Question

a wooden box has external dimensions 40 cm by 34 cm by 30 cm. if the wood is 1 cm thick how many cm3 of wood is used in it ?​

Answer 1

Total Volume = 5688cm^3 without Lid

Total Volume = 6752cm^3 with lid

Explanation:

Front and Back

Length = 40, Width = 34, Height (thickness) = 1

V = L*W*H

V = 40*34*1

V = 1360cm^3

Times 2 for front and back

V = 2720cm^2

Left and Right Side

Because the Front and Back are 1cm thick. You need to subtract 2cm from the length

Length = 28 not 30, Width = 34 (does not change), Thickness = 1

V = 34*28*1

V = 952cm^3

Times 2 for Left and Right

V = 1904cm^3

Bottom

Because the Thickness of the Front and Back, subtract 2 from length, then subtract 2 from width because of the sides being 1 cm thick too.

Length = 28 not 30 (subtract from original outside dimension), Width = 38 not 40, Thickness = 1

V = 28*38*1

V = 1064cm^3

If there was a wooden lid multiply by two

V = 2128cm^3

Total Volume = 5688cm^3 without Lid

Total Volume = 6752cm^3 with lid

Answer 2

6752 cm³ of wood

Explanation:

V = 40cm×34cm×30cm = 40800 cm³

v = 38cm×32cm×28cm = 34048 cm³

V - v = 40800cm³ - 34048cm³ = 6752 cm³ of wood