This is probably wrong, but from what I know, there are 16 vertices, 24 edges, and 10 faces. I’m not sure if this is wrong, but I did some math and some research, and this is what I got.
Answer:
X- axis is the line at the bottom of the graph and y-axis is the line on the side
Given:
Wall 1 & 2 : 26 ft by 9 ft
Wall 3 : 18 ft by 9 ft
Area 1 : 26 ft x 9 ft = 234 ft²
Area 2 : 26 ft x 9 ft = 234 ft²
Area 3 : 18 ft x 9 ft = 162 ft²
Total Area : 234 ft² + 234 ft² + 162 ft² = 630 ft²
1 Gallon = 250 ft²
630 ft² ÷ 250 ft² per gallon = 2.52 gallons