If 90 is 80 percent of the value what is the value

If 90 is 80% of the whole value, then 1/4 of 90 added to 90 will be the value, because 1/4 of 80% (which is 20%) added to 80% will give us 100%

So,

90/4=12.5

90 + 12.5=102.5

At least, that's my take on it