Answer:

Step-by-step explanation:
We have a circle that is split in three sections, two of which we know and we are asked to find the third missing section.
For the circle, we know that 4/5 and 1/10 is fit. Now we need the last one, to solve, we need to get the same denominator and see how much is missing.
Since 1/10 is our highest denominator, let's change 4/5 to have 10 as a denominator. Which would be through multiplying 5 to get 10.
What times 5 equals 10?
2
Now multiply both numerator and denominator by 2 to get our portion.


Now we have the same denominator, let's add our two fractions and see how much we have left.
8/10 + 1/10
9/10
We have 1/10 missing, therefore 1/10 is the answer.
The scale factor 0.05 refers to length, so for area the scale factor is 0.05²=0.0025.
We then multiply: 220 ft²*0.0025=0.55 ft² (choice A)
312* 17.5= 5460.00
134*19=2546
2546+5460= $8,006.00