We are given cost of 150 feet wire = $19.20.
Let us find cost of 1 foot of wire.
In order to find the cost of 1 foot of wire, we need to divide cost of 150 feet wire by 150, that is 19.20/150.
On dividing 19.20 by 150, we get $0.128.
Therefore, cost of 1 foot of wire = $0.128.
Now, we need to find cost of 45 feet wire.
In order to find the cost of 45 feet wire, we need to multiply 45 the unit cost of wire, that is $0.128.
Therefore, cost of 45 feet wire = 45 × 0.128 = $5.76.