Answer:
9600 square inches.
Step-by-step explanation:
We have been given that a puzzle contains a triangular piece with a base of 3 in. and a height of 4 in.
The would used for each triangular piece would be equal to area of triangle.
[tex]\frac{1}{2}\times 3\text{ in}\times 4\text{ in}=3\text{ in}\times 2\text{ in}=6\text{ in}^2[/tex]
Each puzzle contains 20 triangular pieces, so wood used for each piece of puzzle would be 20 times 6 square inches.
[tex]\text{Wood used for each puzzle}=20\times 6\text{ in}^2[/tex]
[tex]\text{Wood used for each puzzle}=120\text{ in}^2[/tex]
[tex]\text{Wood used for 80 puzzles}=80\times 120\text{ in}^2[/tex]
[tex]\text{Wood used for 80 puzzles}=9600\text{ in}^2[/tex]
Therefore, 9600 square inches of wood is needed to make 80 puzzles.
