First of all the Rema says:
“it is permissible to now and then study secular wisdom, provided that this excludes works of heresy… and that one [first] knows what is permissible and forbidden, and the rules and the mitzvot” YD:246:4
“The Gaon considered secular knowledge to be a vital adjunct to Torah study. He was knowledgeable in almost all secular fields and authored books on grammar and mathematics. ” The Short Vort, R’ Eisenmann from Passaic
R’ Hershel Schachter – “What is the relationship between secular knowledge, and a proper derekh
halimmud?
The Vilna Gaon is quoted as saying that to the extent one is lacking in secular
knowledge of the sciences, and so on, one is lacking a hundred times more in
Torah. There are certain areas where secular knowledge is essential. A good example
would be in the area of kashrus. In order to paskin the laws of kashrus, one must have
an understanding of food chemistry.
Rabbi Soloveitchik once spoke at an RCA convention, and dealt with the issue of
shuls that permitted the use of a microphone on Shabbos. He said that, with regard to
those who permitted the use of a microphone, he wondered whether they understood
the Halakha well enough to permit this; with regard to those who prohibited the use of a
microphone, he wondered whether they understood physics well enough to prohibit
this.”
There are many others, but you get my drift.