To find the surface area of the prism-shaped cheese wedge, we need to calculate the area of each of the five faces of the prism and then add them together.
The formula for the surface area of a rectangular prism is:
Surface Area = 2lw + 2lh + 2wh
where l = length, w = width, and h = height.
Given dimensions:
Length (l) = 12cm
Width (w) = 9cm
Height (h) = 5cm
Slant height of the wedge = 13cm
Now we calculate the surface areas of each face of the cheese wedge:
1. Top face: l x w = 12cm x 9cm = 108 cm^2
2. Bottom face: l x w = 12cm x 9cm = 108 cm^2
3. Front face: w x h = 9cm x 5cm = 45 cm^2
4. Back face: w x h = 9cm x 5cm = 45 cm^2
5. Slant face: triangle area = 1/2 x base x height = 1/2 x 12cm x 5cm = 30 cm^2
Now, let's calculate the total surface area:
Surface Area = 2(108) + 2(45) + 2(30) = 216 + 90 + 60 = 366 cm^2
Therefore, 366 square centimeters of plastic wrap will be needed to cover the wedge of cheese.