Answer:
8.4 dollars
Step-by-step explanation:
The error is in the resolution of the proportion. In fact, the initial proportion is correct:

where x is the total cost. However, the following step of the resolution is wrong. In fact, the correct resolution is the following:
- Multiplying by x on both sides:

- Multiplying by 3.5 no both sides:

And now we can find x:

So, the total cost is 8.4 dollars.
To figure this out first make the 4 4/9 into a improper fraction making it 40/9 and then multiply 2/7 x 40/9 then make is a mixed fraction :) hope this helped.
Answer:
120
Step-by-step explanation:
The area of a rectangle is its width multiplied by its length, which in this case is 12*10=120.
Answer:
That's the symbol for pi
Step-by-step explanation:
9514 1404 393
Answer:
x = 39
Step-by-step explanation:
The Pythagorean theorem tells you the sum of the squares of the sides of a right triangle is the square of the hypotenuse.
x² +80² = 89²
x² = 89² -80² = 7921 -6400 = 1521
x = √1521
x = 39