Answer:
He can make 3 birdhouses if he has 12 feet of wood.
Explanation:
Given:
Henry uses 3 feet of wood to make 3/4 of a birdhouse.
If he has 12 feet of wood.
Now, to find the birdhouses he can make.
So, to get the number of birdhouses we use unitary method:
Henry uses 3 feet of wood to make
of a birdhouse.
So, in 1 feet of wood to make =
=

Thus, in 12 feet of wood =
=

Therefore, he can make 3 birdhouses if he has 12 feet of wood.