About 219 gallons (to the nearest gallon) will be 3/4 full
Firstly, we need to calculate the volume of water that the tank will take
Mathematically, this is the product of the three sides of the tank
We have this as;
[tex]6\times5\times1.3=39ft^3[/tex]Now, we need to convert this to gallons
Mathematically, 1 cubic ft is 7.481 gallons
Thus, we have that 39 cubic foot will be;
[tex]39\times7.481\text{ = 291.80 gallons}[/tex]Now, we need 3/4 of this volume
Mathematically, we have this as;
[tex]\frac{3}{4}\times291.8\text{ = }218.85\text{ gallons}[/tex]