So... hmmm if you check the first picture below, for 2)
we could use the proportions of those small, medium and large similar triangles like

now.. for 3) will be the second picture below
19.98 rounded to the nearest whole number is 20.
In the number 19, 9 round the 1 to a 2 and the 9 becomes a 0 because of the 9 behind the decimal.
OR
You could think of a percent being 100. 98 is only 2 numbers away from 100 and thus you can round 19 up to 20.
Hope this helps! (:
If this is a question about who is correct Clair is correct
do u need all the answers?