Step-by-step explanation
We must find the amount of cardboard needed to make a slice of pizza box which basically means finding the surface area of the piece of box shown. This is composed of five faces divided in three groups:
- Two equal triangular faces with a base of 6.7 in and a height of 11 in.
- Two equal rectangular faces with a base of 11.5 in and a height of 1 in.
- A single rectangular face with a base of 6.7 in and a height of 1 in.
The area of the piece of box is given by the sum of the areas of the 5 faces so let's find the area of the faces of each group.
The area of a triangle is given by half the product of the length of its base and its height. Then the area of each triangular face is:
So each triangular face has an area of 36.85 in².
The area of a rectangle is given by the product of its base and height. Then for the pair of equal rectangular faces we have:
So each of these two faces has an area of 11.5 in².
The area of the remaining rectangular face is then given by:
So the area of the last face is 6.7 in².
Then the total surface area is given by the sum of the areas of the 5 faces. Then we get:
Answer
Then the answer is 103.4