For the first one multiply 20 bye 2.54 and you'll get your first answer.
For the second one covert feet into inches, multiply 25 by 12, then multiply that answer by 2.54. You'll get your answer then.
6) 20inch×2.54cm=50.8cm
7) 25ft×12inch= 300inch, 300inch×2.54cm=762cm
