A puzzle contains a triangular piece with a base of 3 in. and a height of 4 in. A manufacturer wants to make 80 puzzles. Find the amount of wood used if each puzzle contains 20 triangular pieces.

I believe this question asks for the total amount of area of wood that is needed to make 80 puzzles.

The formula for area of triangle is given as:

A = (1 / 2) b h

where,

b = is the base of the triangle = 3 in

h = height of the triangle = 4 in

So calculating for area of 1 on triangle (A1):

A1 = (1 / 2) (3 in) (4 in)

A1 = (1 / 2) 12 in^2

A1 = 6 in^2

We are given that we are to make 80 puzzles and each puzzle has 20 triangles, therefore the total amount of triangles we need to make is:

n = 80 * 20

n = 1600

Therefore the total area needed (A) is:

A = A1 * n

A = 6 in^2 * 1600

A = 9,600 in^2