A science fair poster is a rectangle 36 inches long and 24 inches wide. What is the are of the poster in square feet?

To find the area of the poster in square feet, we need to convert the given dimensions from inches to feet.

Since there are 12 inches in 1 foot, the length of the poster in feet is: 36 inches / 12 inches/foot = <<36/12=3>>3 feet.
Similarly, the width of the poster in feet is: 24 inches / 12 inches/foot = <<24/12=2>>2 feet.

The area of the rectangle is found by multiplying the length and width, so:
Area = 3 feet * 2 feet = <<3*2=6>>6 square feet.

Therefore, the area of the poster is 6 square feet. Answer: \boxed{6}.