A stop sign is in the shape of a regular octagon. A regular octagon can be created using eight triangles of equal area. One triangle that makes up the stop sign has a base of 15 inches and a height of 18 inches. Calculate the area of the stop sign.

The area of one triangle is (1/2) × 15 × 18 = 135 square inches. The regular octagon is made of 8 equal-area triangles, so its area is 8 × 135 = 1,080 square inches. Therefore, the correct choice is 1,080 sq. in.

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