Answer:
1926cm²
Step-by-step explanation:
Given
Dimension = 21cm by 18cn by 15cm
The illustration in this question is to determine the surface area of the fabric and this is calculated using the surface area of a cuboid as follows:
[tex]Surface\ Area =2(LB + LH + BH)[/tex]
Where L, B and H are the dimensions.
So,
[tex]Surface\ Area = 2(21 * 18 + 21 * 15 + 18 * 15)[/tex]
[tex]Surface\ Area = 2(378 + 315 + 270)[/tex]
[tex]Surface\ Area = 2(963)[/tex]
[tex]Surface\ Area = 2 * 963[/tex]
[tex]Surface\ Area = 1926cm\²[/tex]
Hence, 1926 cm² of fabrics are needed to cover all surfaces.