Question

Question #b3ab8

Answer 1

`~~$896.4`

Explanation:

Let the number be `x`
`$645.40=72%xx x`
`72%xx x=$645.40`
`1%xx x=$645.40-:72`
`~~$8.963888...`

`100%xx x=$8.963888...xx100`
`=896.3888...`
`~~896.4`

Answer 2

`x = $896 7/18` as an exact value

`x=$896.39` as an approximate value

Explanation:

The sign or symbol of % is like a unit of measurement but one that is worth `1/100`

So `1/100` and % are interchangeable.

The word 'of' is a bit like counting. 2 of apples `->2xx"apples"`
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Let the unknown value of dollars be `x`

So `72%" of "x` is the same as `72%xx x`

Then we have `72/100xx x =$645.40`

Multiply both sides by `100/72` (turns the `72/100` on the left into 1)

`72/100xx100/72xx x =100/72xx$645.40`

`72/72xx100/100xx x =100/72xx$645.40`

`1xx1xx x = $896 7/18` as an exact value

`x=$896.39` as an approximate value