dpkg -S will only tell you about files in packages that are already installed. You need something that will tell you about files in packages that you do not have installed. apt-file is such a tool.
You need to install it, apt-get install apt-file, then apt-file update, then apt-file search latex.
apt-file search /usr/bin/latex
latex-mk: /usr/bin/latex-mk
latex209-bin: /usr/bin/latex209
latex2html: /usr/bin/latex2html
latex2rtf: /usr/bin/latex2png
latex2rtf: /usr/bin/latex2rtf
latexdiff: /usr/bin/latexdiff
latexdiff: /usr/bin/latexdiff-cvs
latexdiff: /usr/bin/latexdiff-fast
latexdiff: /usr/bin/latexdiff-git
latexdiff: /usr/bin/latexdiff-hg
latexdiff: /usr/bin/latexdiff-rcs
latexdiff: /usr/bin/latexdiff-svn
latexdiff: /usr/bin/latexdiff-vc
latexdiff: /usr/bin/latexrevise
latexdraw: /usr/bin/latexdraw
latexila: /usr/bin/latexila
latexmk: /usr/bin/latexmk
latexml: /usr/bin/latexml
latexml: /usr/bin/latexmlc
latexml: /usr/bin/latexmlfind
latexml: /usr/bin/latexmlmath
latexml: /usr/bin/latexmlpost
liblatex-decode-perl: /usr/bin/latex2utf8
liblatex-driver-perl: /usr/bin/latex2dvi
liblatex-driver-perl: /usr/bin/latex2pdf
liblatex-driver-perl: /usr/bin/latex2ps
liblatex-encode-perl: /usr/bin/latex-encode
texlive-extra-utils: /usr/bin/latex-git-log
texlive-extra-utils: /usr/bin/latex2man
texlive-extra-utils: /usr/bin/latexdef
texlive-extra-utils: /usr/bin/latexfileversion
texlive-extra-utils: /usr/bin/latexindent
texlive-extra-utils: /usr/bin/latexpand
texlive-latex-base: /usr/bin/latex
tth-common: /usr/bin/latex2gif
The package you are looking for is second to last in this list, namely texlive-latex-base. Then you just need to do apt-get install texlive-latex-base. This is one of the TeX Live packages. Though for TeX Live, you're probably better off just installing the texlive metapackage. Namely apt-get install texlive.
I don't think ratfor90 is available on Debian, at least. I'm not sure about Ubuntu. And as far as acroread goes, give either okular or evince a try. I use okular.