Andre is creating a border around his rectangular patio with paver bricks. The coordinates of the vertices of the patio are (1, 5), (6,5), (6,1), and (1, 1). Each grid square has a length of 3 feet. Find the amount of brick, in feet, needed for the perimeter.

The given coordinates are (1, 5), (6, 5), (6, 1) and (1, 1). Draw a rectangular figure using these coordinates.

The measurements of each side are 4, 4,5, and 5. Therefore the perimeter of the patio is:

4 + 4 + 5 + 5 = 16 feet

If each grid of the square is 3 feet. The measurement of the upper part of the patio is 5 + 3 + 3 = 11 feet. The other side is 3 + 3 + 4 = 10 feet. So the total area of the patio plus the bricks is 10 x 11 = 110 sq. feet. The area of the patio is 4 x 5 = 20 ft.

Therefore, the remaining area is 110 - 20 = 90 ft.