Answer:
(b) 96 inches
Explanation:
The perimeter of the board is the sum of its four edge lengths.
Edge length
Each edge of the board is indicated as being 8 squares long. Each square is 3 inches on a side, so the edge of the board is ...
8 × (3 in) = 24 in . . . . board edge length
Perimeter
The perimeter of the board is 4 times the length of one edge, so is ...
P =4s = 4(24 in) = 96 in
The perimeter of Edgar's checkerboard is 96 inches.
__
Scaled geometry (alternate solution)
The perimeter of one small square on the board is ...
P = 4s = 4(3 in) = 12 in
The whole board is a dilation of one square by a factor of 8. Its perimeter will be ...
P' = (scale factor) × P
P' = 8×(12 in) = 96 in
The perimeter of Edgar's checkerboard is 96 inches.