Question

surface area cubes, prisms & pyramids 1
find the surface areas of these shapes.
1)
surface area
2
surface area

Explanation:

Step1: Calculate the area of each face

The formula for the area of a rectangle is \(A = l\times w\).
For the face with \(l = 8\mathrm{cm}\) and \(w = 4\mathrm{cm}\), \(A_1=8\times4 = 32\mathrm{cm}^2\).
For the face with \(l = 8\mathrm{cm}\) and \(w = 5\mathrm{cm}\), \(A_2=8\times5=40\mathrm{cm}^2\).
For the face with \(l = 5\mathrm{cm}\) and \(w = 4\mathrm{cm}\), \(A_3 = 5\times4=20\mathrm{cm}^2\).

Step2: Use the surface - area formula for a rectangular prism

The surface - area formula of a rectangular prism is \(S=2(A_1 + A_2+A_3)\).
Substitute \(A_1 = 32\mathrm{cm}^2\), \(A_2 = 40\mathrm{cm}^2\), and \(A_3 = 20\mathrm{cm}^2\) into the formula:

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Answer:

\(184\mathrm{cm}^2\)