There are 400 books 20 of them got taken how many are left

 380 books left.

Step-by-step explanation:

 Data Given:

  total number of books  = 400

  books to be taken away  =  20

 To Find:

  books left out  =  ?

 Solution:

   Answer is obtained simply by using basic arithmetic operation of                          Subtraction

     400 -  20 = 380

< coa = 150 ( given)

as ba and bc are tangents

so oc and oa is perpendicular to cb and ab respectively because in circle normal passes through centre

so in quadrilateral oabc

< coa + < oab + < ocb + < abc = 360

150 +90+90 + < abc = 360

330 + < abc = 360

< abc = 360 -330 = 30

so < abc = 30

⭐dhruv⭐

answer: plz give a pic and answer choices so i can answer!

step-by-step explanation: