The cross product of two vectors gives a third vector

that is orthogonal to the first two.

Normalize this vector by dividing it by its norm:

To get another vector orthogonal to the first two, you can just change the sign and use

.
Square root 144 = 12 so this is the rational number
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
the answer is 2• 137= 274