6-4=2
5-X=?
5-2=3
X=3
That is the answer, sorry if i didn't explain it well<span />
They are the same one is just curved.
Hope this helped!!
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
2912 is the population . when 12% is increase of the Ann's population