Answer:
 1) Newbury Park → The distance is accurate.
 2) Thousand Oaks → The distance is not accurate.
 3) Los Angeles → The distance is not accurate.
 Step-by-step explanation:
 It is important to remember that:
 
 Knowing this, you can make the corresponding conversions:
 1) Newbury Park
 10 miles to kilometers:
  
 
 The distance shown in that California highway sign is accurate.
 2) Thousand Oaks
 13 miles to kilometers:
  
 
 The distance shown in that California highway sign is not accurate.
 3) Los Angeles
 55 miles to kilometers:
  
 
 The distance shown in that California highway sign is not accurate.