Split a 20 decimeter long cylindrical wood along the bottom diameter, and increase the surface area by 80 square decimeters. What is the original surface area of this cylindrical wood? (π = 3)

Split a 20 decimeter long cylindrical wood along the bottom diameter, and increase the surface area by 80 square decimeters. What is the original surface area of this cylindrical wood? (π = 3)

The diameter of the bottom surface of the original cylindrical wood is: 80 △ 2 △ 20, = 2 (decimeter); the bottom area of the original cylindrical wood is: 3 × (2 △ 2) 2 = 3 (square decimeter); the side area of the original cylindrical wood is: 3 × 2 × 20 = 120 (square decimeter); the surface area of the original cylindrical wood is: 3 × 2 + 120 = 126 (square decimeter). A: the surface area of the original cylindrical wood is 126 square meters Decimeter