Change size of the inline image for Latex fragment in emacs org-mode

I have this in my .emacs:

;; bigger latex fragment
(plist-put org-format-latex-options :scale 1.5)

The answer from thisirs didn't work for me. The post is a bit old, so I guess it worked on an older version of org-mode. The following worked for me in Org mode version 9.1.9:

Pressing M-x customize-variable org-format-latex-options brings up the customization editor where I was able to set the scale to 1.5

This is what ended up in my .emacs file afterwards:

 '(org-format-latex-options
   (quote
    (:foreground default :background default :scale 1.5 :html-foreground "Black" :html-background "Transparent" :html-scale 1.0 :matchers
         ("begin" "$1" "$" "$$" "\\(" "\\["))))