What is 7/8 times a variable that has to equsl to 8

Hello!  

We have the following data:  

if: 1 ft = 12 in

So:  

x: 13 '' = 13 * (12 '') + 3 '' = 156 '' + 3 '' = 159 '' (inches)  

y: 11 ft 5 in = 11'5 "= 11 * (12") + 5 "= 132" + 5 "= 137"  (inches)

Now, let's calculate the Area, let's see:  

A = x * y

A = 159 * 137

A = 21783 in²

Let's transform square inches into square feet, we have:  

1 in² 0.00694 ft²

21783 in² A

A = 21783 * 0.00694

A ≈ 151.17 ft² ← (answer)

I Hope this helps, greetings ... DexteR! =)